Eco-friendly Printing Ink

Printing ink from vegetable oils is a good replacement for the mineral-based ink used currently. Vegetable oil is environment friendly, claims a study. “It will reduce the organic compounds released during printing,” says Santinath Ghosh from the department of Chemical Technology at the Calcutta University.

“Volatile organic compounds leads to formation of smog in printing units, which pose serious health hazards to workers,” says Ghosh who led a joint research team from the university and Kolkata-based dic India Limited. dic is the biggest manufacturer of natural ink in the country. The volatile organic compound also affects the ozone layer.

The study says that the ink is more stable than its mineral-based counterpart.

It dries faster and gives a good image quality. It also helps conserve non-renewable petroleum oils. Mineral oil-based ink uses non-renewable petroleum oils, which make up for 30 per cent of the offset printing inks in the graphic art industry.

For the study, the team developed several printing inks using vegetable oils such as rapeseed, soybean, palm oil and rice bran, and mixing other chemical ingredients such as phenolic-resins and polyethylene wax paste. Resins were added to the vegetable oil.

When the results were compared, it was found that the products using vegetable oils—rice bran oil and palm oil—produced better results in terms of stability, and quality of print. Although the cost of the ink will be 8-10 per cent more than mineral oil-based product, it will avoid a lot of occupational problems, including improving the health of printing workers.

The above article was originally published in 15 January 2008 issue of Down To Earth, a science and environment fortnightly

Sunderbans polluted: Persistent organic pollutants found

Rising sea level and erosion aside, the Sundarbans now face a new threat. An international research team has detected polybrominated diphenyl ethers (pbde), a persistent organic pollutant, in the core sediment from seven sites in the wetland. pbdes are used as flame-retardants in electrical equipments, plastics, textiles, building materials, vehicles and aircraft industries. Earlier research has established that pbdes can be persistent, bioaccumulative and toxic. They can cause liver and neuro-developmental toxicity and affect thyroid hormone levels.

“The huge discharge of municipal wastewater along with local industries’ waste may have contributed to elevated levels of pbdes. The presence of several textile plants along the upper stretch of Hooghly estuary indicates local use of pbde formulates for textile production,” says Santosh Kumar Sarkar, a co-researcher at the department of marine sciences in the Calcutta University, in a study published in the recent issue of Marine Pollution Bulletin (Vol 54, No 8).

Sarkar says, among the 12 kinds of pbdes found, the penta-bde mixture is most dangerous. “We will give due emphasis on the risks of exposure to wildlife species and humans now,” he adds. He feels the results will help monitor the wetland for more persistent organic pollutants.

The above article was originally written by this blogger and published in the 15th October 2007 issue of Down To Earth, a science and environment fortnightly published from New Delhi

Human Urine Aids the Growth of Fish Food Organism

A research team from West Bengal has discovered that human urine could be an excellent liquid waste aid in the mass production of fish food organism called Moina micrura, a type of zooplankton. The team studied the nutrient potentials of human urine and then compared its efficacy with other waste products like cow urine, human-cow mixed urine, vermin-compost, cow dung, poultry droppings and mixed wastes (vermin-cow-poultry) for the mass culture of M. micrura in 24 outdoor tanks.

The team found that the newly born M. micrura held in the treatment with human urine started reproduction at least 4 days earlier than other solid wastes. Total number of M. micrura counted in the culture tank, related with offspring production per life span, was maximum in case of human urine treatment, followed by human–cow mixed urine, cow urine, vermin-compost, poultry droppings, mixed wastes (vermin–cow–poultry), cow dung and control treatments.

The relationship between the total offspring production per female per life span and the nitrogen content of water in different treatments implied that human urine can be used for the mass production of zooplankton Moina micrura required for larval and post larval rearing of commercial fishes, write the researchers in a recent issue of Ecological Engineering.

A Potential Remedy for Malignant Malaria

A research team from Kolkata has discovered a complex organic compound that inhibits the activity of an enzyme that is essential for the survival and growth of Plasmodium falciparum, a parasite that causes malignant malaria in humans. According to the research team, the compound called hexadecyltrimethylammonium bromide (HDTAB) disrupted the activity of the enzyme called choline kinase, an enzyme which plays vital role in the biosynthesis of the most essential phospholipid, phosphatidylcholine in P. falciparum.

HDTAB inhibited P. falciparum choline kinase (PfCK) in a dose-dependent manner and offered very potent antimalarial activity in lab studies against P. falciparum. Furthermore, the antimalarial activity of HDTAB paralleled the decrease in phosphatidylcholine content, which was found to correlate with the decreased phosphocholine generation. These results suggest that inhibition of choline kinase by HDTAB leads to decreased phosphocholine, which in turn causes a decrease in phosphatidylcholine biosynthesis, resulting in death of the parasite.

Moreover, HDTAB exhibited profound antimalarial activity in vivo against the rodent malaria parasite Plasmodium yoelii (N-67 strain). Interestingly, parasites at the trophozoite and schizont stages were found to be particularly sensitive to HDTAB, write the researchers in a recent issue of Antimicrobial Agents and Chemotherapy.

Malaria is still a burning problem in India and other developing countries and second biggest killer after tuberculosis. Till November 2006, nearly 1.04 million Indians were afflicted with malaria. Of all the malaria cases, .46 million cases were P. falciparum cases. Some of the states like MP, Orissa, A.P., West Bengal, Gujarat, North Eastern States, Bihar and Maharashtra are highly endemic for P. falciparum and these states contribute around 97 per cent of the total P. falciparum cases in the country.

Since the 1990s, malaria returned with vengeance. The new obstacles have been resistance in P. falciparum to chloroquine and other anti-malarial drugs and human resistance to chemical control of vectors. Malaria control has become a complex enterprise.

Malaria also causes huge economic loss in a country like India. India has spent up to 25 per cent of its health budget on malaria control from 1977-1997. In 1997, India also started a five-year program for malaria control aimed to target 100 districts where 80 per cent of all P. falciparum cases occur.

Herbal Cure for Amoebiasis


Indian camphorweed, that grows in lowlands and swamps, may hold the key to a cure for amoebiasis, a disease caused by the parasite Entamoeba histolytica that mostly hits the poor. A team of researchers from Jadavpur University and Indian Institute of Chemical Biology, both in Kolkata, have isolated a compound from the root of this plant that stops the growth of the parasite.

Among the seven compounds isolated from the root extract of the shrub (Pluchea indica) is r/j/3.

“This pure compound, chemically a thiophene derivative, was most effective in checking the proliferation of the parasites,” says lead researcher Tapan Kumar Chatterjee.

This could be a potent anti-amoebic drug, he says. The findings of the study will be published in a forthcoming issue of Phytomedicine.

The researchers took a virulent strain (hm1) of E histolytica and cultured trophozoites, the stage in which the parasite resides in the intestine and causes symptoms of amoebiasis. Then they exposed the trophozoites to varying doses of the pure compound.

r/j/3 showed optimum result at a dose of 0.00005 gm per ml. Two hours after administration, it caused granulation in the trophozoites. In four hours, the trophozoites were completely broken down. r/j/3 acted slower than synthetic drugs like metronidazole. “But being a plant product, it is safe and non-toxic. Metronidazole is very toxic and parasites are sometimes resistant to it,” Chatterjee says.

The above article was originally published in Down To Earth, a science and environment fortnightly published from New Delhi and written by this blogger.

Aloe vera could cure Kala-azar

known for its cosmetic applications, aloe vera, the wonder plant, has now been found to possess ingredients that can cure kala-azar and some other forms of leishmaniasis. Ghrita Kumari, as the plant is locally known, can kill two forms of leishmania parasites, researchers from Kolkata’s Institute of Post Graduate Medical Education and Research and Indian Institute of Chemical Biology have found. Leishmaniasis is a disease caused by protozoan parasites that belong to the genus Leishmania and is transmitted by certain species of sand fly.

In laboratory experiments, the team found that leaf extracts of the aloe vera plant directly killed two kinds of parasites, promastigotes and amastigotes. The promastigote form enters the human body through sand-fly bites and morphs into amastigote inside the macrophage cells, a type of immune cells derived from while blood cells.

This causes kala-azar or leishmaniasis with symptoms like fever, loss of appetite and enlarged spleen and liver.

“Aloe vera extracts activated cultured mice macrophages increasing the production of toxic metabolites of oxygen like superoxide anions, hydrogen peroxide and nitric oxide,” says Mitali Chatterjee, lead co-author of the study. “I feel that these toxic metabolites help generate oxidative stress-destroying leishmania parasites inside the macrophages,” she says. According to her, the study has immense potential as aloe vera is easily available and its toxicity is low. Aloe vera, she says, could be a potential herbal remedy for kala-azar and other types of leishmaniasis.

To study the efficacy of aloe vera extract, five parasitic strains including k27 and jish 118 were isolated from patients with cutaneous leishmaniasis, lv81 and l280, from patients with mucocutaneous leishmaniasis while mon 29 and 2001 were isolated from patients with visceral leishmaniasis.

After culling promastigotes from patients, the team converted them into amastigotes in culture media outside macrophage cells. Then promastigotes and amastigotes were exposed to various concentrations of the plant leaf extract. “The extract possesses a direct parasiticidal effect on leishmania promastigotes, irrespective of the species, suggesting its efficacy in all forms of leishmaniasis,” comments Chitra Mandal, one of the authors.

The potency of the extract to kill leishmania amastigotes was over 25-fold higher than in promastigotes, write the researchers in Glycoconjugate Journal (Vol 24, No 1). This was significant, considering amastigotes are responsible for the disease.

According to the researchers, the study is significant as available anti-lesihmanial therapy has drawbacks like toxic side-effects, high cost and drug-resistance. Aloe vera could be an effective antidote to kala-azar, which according to the National Vector Borne Disease Control Programme, puts 165.4 million people at risk in Bihar, Jharkhand, Uttar Pradesh and West Bengal.


The above article was originally published in the 30 April 2007 issue of Down To Earth, a science and environment fortnightly published in New Delhi and written by this blogger.

Scorpion Venom Antidote to Blood Cancer


venom spewed by the deadly Indian black scorpion (Heterometrus bengalensis) could have a possible cure for human blood cancer, a new research claims.A joint team from Indian Institute of Chemical Biology, Kolkata, and University of Calcutta found in laboratory tests that venom from the black scorpion stopped the proliferation of cultured human blood cancer cells and drove them to commit mass suicide (apoptosis or programmed cell death).

“This is the first report of anti-cancer potential of Indian black scorpion venom from India,” says Aparna Gomes, who led the research. “We have already identified that the anti-cancer effects of scorpion venom are due to the presence of certain proteins,” says Antony Gomes, co-author of the study to be published in a forthcoming issue of Leukemia Research.

The researchers are working to decipher the identity of the anti-cancer proteins in scorpion venom and find how those proteins inhibit the growth of cancer cells. This provides clues to the development of a new anti-cancer drug.

The researchers cultured two types of human leukaemic cell lines (u937 and k562) and exposed them to doses of scorpion venom for 48 hours. The team took two million of each type of leukaemic cells. The u937 cells were exposed to 0.0000415 gram/ml of scorpion venom and k562 cells to 0.0000883 gram/ml. A batch of unexposed leukaemic cells was treated as controls. The study found that both the doses of venom halted the growth of 50 per cent of the cancer cells. Sophisticated imaging techniques revealed that the venom-treated cancer cells underwent controlled death.

The control cancer cells showed intact cell membrane, but the treated cells clearly showed deep ridges and furrows as well as severe membrane bulging, the hallmark of mass death. The treated cells had damaged nuclei as well as fragmented dna compared to intact ones of controls. The venom also arrested the cell cycle reducing the dna content of the cancer cells.

Such study results are encouraging. “Of the 90 species of venomous Indian scorpions, we have seen only one species,” says Antony Gomes. He believes that more effective anti-cancer drugs can be made by studying venoms.

A cheap anti-leukaemic drug is urgently needed as the National Cancer Registry has identified leukemia among ten of the leading cancers in Delhi, Aurangabad, Barshi, Bangalore, Nagpur and Thiruvananthapuram.

The above article was originally published in 'Down To Earth', a science and environmently fortnightly and written by this blogger

Nanoparticles Could Help in Screening Individuals for Thalassaemia

A type of nanoparticles could provide clues to whether a person carries the defective gene for thalassaemia, claims a research team from Kolkata-based Calcutta University. Known as copper nanoparticles (CuNPs), the nanomolecules form various protein aggregates binding to haemoglobin, the metalloprotein in red blood cells. Besides protein aggregrates, the copper nanoparticles also precipitate the aggregated protein.

The researchers found that the nanoparticles formed a distinct aggregation when bound to a mutated form of haemoglobin that leads to beta-thalassaemia. Using special techniques like atomic absorption spectroscopy and high-pressure liquid chromatography, the team found the nanoparticles were co-precipitated with specific variants of haemoglobin. Studies showed that protein initially broke the nanoclusters into smaller sizes (4nm), followed by gradual increase in cluster size. A suitable scaling up of the approach may have important implications in screening haemoglobinopathies such beta-thalassaemia, write the researchers in a recent issue of Nanomedicine.

According to an estimate, there would be about 45 million carriers and about 15,000 infants born each year with haemoglobinopathies in India. The carrier frequency of haemoglobinopathy varies from 3 to 17 per cent in different population groups of India. In India, beta-thalassaemia comprises about 80–90 per cent of the total thalassaemias reported. More than 200 beta-thalassaemia mutations have been identified all over the world and of these about 28 mutations have been documented in Indian patients. There is growing concern that thalassemia may become a very serious problem in the next 50 years.

Antidote to Infertility from Buffalo Blood

A protein isolated from buffalo blood induces forward motility of goat sperm, en essential quality that makes fertilisation possible in animals and humans, claims a research team from the Indian Institute of Chemical Biology, Kolkata. Known as the forward motility stimulating factor (FMSF), it has been shown to activate goat spermatozoa.

“FMSF can be used to enhance fertility in animal breeding farms and human infertility clinics,” says Gopal Chandra Majumder, the lead author. “The motility-promoting efficacy of FMSF is higher than non-protein activators like theophylline and bicarbonate. Besides, it is not species specific,” Majumder adds. FMSF, according to him, also has the potential for improving breeding of wild animals, and should help species that are almost extinct or endangered.

After isolation from buffalo blood fluid, FMSF was purified and exposed to goat sperm incubated in plasma. The team found two types of FMSF (FMSF-I, FMSF-II). Nearly 20-30 per cent goat spermatozoa showed forward progression in the absence of FMSF-I. The addition of it enhanced sperm forward motility significantly.

“The motility-promoting action is nearly complete in about one minute compared to other motility-promoting factors (theophylline and bicarbonate), which take six minutes to initiate maximal forward motility of sperm,” says Majumder. Mostly synthesized in liver, FMSF-I stimulates the motility of sperm of goat, rat, and humans. This shows that it has a certain regulatory role on sperm physiology. FMSF-I contains protein and sugar, both of which contribute to its motility-promoting factor, he says.

“Study reveals that FMSF-I binds to the receptor protein on sperm cell surface, which activates a second messenger protein, which in turn triggers a cascade of cellular events inside the sperm inducing forward motility,” explains Majumder in a paper published in the November issue of Journal of cellular Physiology (Vol 209, No 2).

The above article was originally published in ‘Down to Earth’, a science and fortnightly published from New Delhi and originally written by this blogger.

Scientists Snap an Image of a Piece of HIV Protein

In a groundbreaking discovery, for the first time researchers from the National Institute of Allergy and Infections Diseases (part of National Institutes of Health), Dana-Farber Cancer Institute in Boston, and The Scripps Research Institute in La Jolla have crystallized and captured an atomic-level picture of a key portion of an HIV surface protein as it looks when bound to an infection-fighting antibody. Unlike much of the constantly mutating virus, this protein component is stable and -- more importantly, say the researchers -- appears vulnerable to attack from this specific antibody, known as b12, which can broadly neutralize HIV.

This finding, one of the best leads to come along in years, shows us a critical area of vulnerability on the virus that may be used to target with vaccines, sum up the researchers.


This neutralizing antibody binds to a HIV surface protein called gp120. Until now, no one had succeeded in determining the detailed structure of b12 in complex with gp120. It was extremely difficult to crystallize b12 bound to gp120, say the researchers in the 15 February online issue of Nature, in part due to the inherently flexible nature of the chemical bonds in gp120. To overcome the problem, the investigators created a variety of gp120s and eventually made the protein stiff enough to capture a picture of it in complex with b12. They saw that b12 binds gp120 at the same point where gp120 initially attaches to CD4 (a type of host’s cell surface protein).

Folic Acid May Prevent Cleft Lip and Palate in Infants

Gulping down leafy vegetables, citrus fruits, beans, and whole grains early in their pregnancy can help women reduce their baby’s chances of being born with a facial cleft, claims a team of researchers from the National Institute of Environmental Health Sciences (NIHES), part of the National Institutes of Health. The NIEHS team found that 0.4 miligrams (mg) a day of folic acid, which is found in leafy vegetables, citrus fruits, beans, and whole grains could reduce the baby’s risk by one third.

“These findings provide further evidence of the benefits of folic acid for women,” said Allen J. Wilcox, lead author of the study published in the latest British Medical Journal. “We already know that folic acid reduces the risk of neural tube defects, including spina bifida.”

Folic acid is a B vitamin found in leafy vegetables, citrus fruits, beans, and whole grains. It can also be taken as a vitamin supplement, and it is added to flour and other fortified foods. The recommended daily dietary allowance for folate for adults is 400 micrograms or 0.4 mg.

“Folic acid deficiency causes facial clefts in laboratory animals, so we had a good reason to focus on folic acid in our clefts study,” said Wilcox. This population-based study was conducted in Norway, which has one of the highest rates of facial clefts in Europe and does not allow foods to be fortified with folic acid. In the US, on other hand, about one in every 750 babies is born with cleft lip and/ or palate.

The researchers estimated that 22 percent of isolated either cleft lip with or without cleft palate (CLP) cases in Norway could be averted if all pregnant women took 0.4 mg of folic acid per day.

A New Potential Weapon against TB

A team of researchers from University of Wisconsin-Madison School of Veterinary Medicine, Texas A&M University, and University of Saskatchewan in Saskatoon, Canada has discovered a unique copper-repressing protein in the bacterium that causes tuberculosis in humans. This finding could pave the way for new strategies to halt tuberculosis infection.

When TB bugs invade, host immune cells dump excessive amounts of copper onto the invaders in an effort to kill them. Though all cells need copper, but too much of it causes cell death. But the present study has found that the TB bugs fight back by generating a copper-repressing protein. This helps the TB bugs block excess copper in host’s body. With this discovery, we can now pursue ways to deactivate the repressor protein leading to novel antidote to tuberculosis infection, say the researchers in a paper that will appear in January 2007 issue of Nature Chemical Biology.

A Vaccine for Ebola Virus is Safe in Healthy Adults

A DNA vaccine for Ebola virus was found to be safe in healthy adults, according to a study published in the November issue of journal Clinical and Vaccine Immunology. The vaccine developed by a research team from Vaccine Research Centre at National Institute of Allergy and Infectious Diseases, Bethesda, Maryland and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington was well-tolerated, with no significant adverse events or coagulation abnormalities.

Since 1976, Ebola virus has been spreading panic in developing countries of Africa like the Democratic Republic of the Congo (formerly Zaire) and Sudan. In recent years, it (especially Ebola-Zaire subtype) has surfaced in Uganda, Gabon and The Republic of Congo. This virus is deadly as it causes death in 50 and 90 per cent of all clinically ill cases.


The vaccine encoding the envelope glycoprotein (GP) from the Zaire and Sudan/Gulu species of Ebola virus as well as nucleoprotein was administered to 21 adults aged between 18 and 44. Each healthy volunteer received three injections of the vaccine. Of them, five received at a dose of 2 mg, 8 at 4 mg and 8 at 8 mg and these vaccinated adults were compared with 6 placebo subjects. The treated group showed specific antibody responses as well as generation of lymphocytes (CD8+ T-cell and CD4+ T-cell), a type of white blood cells, which are capable of killing the whole virus and help generate antibodies in response to GP of Ebola virus.

The lurking threat is the natural reservoir of the Ebola virus, which seems to reside in the rain forests of the African continent and in areas of the Western Pacific. On the African continent, Ebola infections of human cases have been linked to direct contact with gorillas, chimpanzees, monkeys, forest antelope and porcupines found dead in the rainforest. So far, the Ebola virus has been detected in the wild in carcasses of chimpanzees (in Côte-d’Ivoire and Republic of Congo), gorillas (Gabon and Republic of Congo) and duikers (Republic of Congo).

As any time, humans can come into contact with this natural reservoir during their day-to-day activities, most of which revolve around forest and wild life. No specific treatment or vaccine is yet available for Ebola haemorrhagic fever. Several vaccine candidates are being tested but it could be several years before any are available. The present study which highlights the safety of a DNA vaccine for Ebola virus, which has wreaked havoc in recent years, is very important and encouraging for developing countries in Africa as well as Asia.

Moon: Dead or Alive?

If you are with conventional wisdom that any volcanic activities on the moon have ceased billions of years ago, then you are mistaken. A new study points to evidence that the moon has been geologically active within the past 10 million years. The site that bears the signs of recent geological activities is ‘Ina’, in Lacus Felicitatis, a lake of ancient, hardened lava located at lunar coordinates 19o N, 5o E, according to a report published in the 9 November issue of journal Nature.

Apollo astronauts first noticed Ina. Since then it became the object of intense scrutiny of astronomers. “It is shaped like a letter D and two kilometers wide,” says Peter Schultz of Brown University in US, who led the research team in uncovering the mysteries of Ina. Several features of Ina prove that it is young. One of them is that Ina has sharp edges. As small meteoroids constantly rain down on the moon’s surface, sharp edges are unlikely to survive. Further, Ina is sparsely cratered. According to Schultz, there are only two clear impact craters larger than 30 meters on the 8 square kilometers of the structure’s floor.

Schultz and his teammates found that patches of lunar regolith in the Ina structure were recently removed. “The number of superimposed small craters and the freshness of the regolith together indicate that features within this structure must be very young and perhaps are still forming today,” concludes Schultz.

Deodorant Damage:Lungs get affected

A CHEMICAL compound found in many air fresheners, toilet bowl cleaners, mothballs and other deodorising products may leave harmful effects on lungs, says a research team from the National Institute of Environmental Health Sciences, a part of the National Institutes of Health in the USA. The team found that exposure to a Volatile Organic Compound called 1, 4 dichlorobenzene (1, 4 DCB) causes reductions in lung function. “Even a small reduction indicates some harm to the lungs,” says Stephanie London who led the study.

“The best way to protect yourself, especially children who may have asthma or other respiratory illnesses, is to reduce the use of products and materials that contain these compounds,” she says.

In search of evidence, she and her team examined the relationship between blood concentrations of 11 common VOCs and lung function measures in 953 adults. VOCs are a diverse set of compounds emitted as gases from thousands of commonly used products, including tobacco smoke, pesticides, paints, cleaning products and also released through automotive exhaust. Of the common VOCs (benzene, styrene, toluene, and acetone), only the compound 1, 4 DCB was linked to reduced pulmonary function, according to the study.

This effect was seen even after careful adjustment for smoking. The researchers found that 96 per cent of the population samples had detectable 1, 4 DCB blood concentration levels. The findings were published in a recent issue of Environmental Health Perspectives.

The VOC (1, 4 DCB) accused of causing damage to lungs is a white solid with distinctive aroma, similar to mothballs used as a space deodorant in products such as room deodorisers, urinal and toilet bowl blocks, and as an insecticide fumigant for moth control.

“Because people spend so much time indoors where these products are used, it is important that we understand the effects that even low levels might have on the respiratory system,” says Leslie Elliot, a researcher involved in the NIEHS study.

The above article was written by this blogger and originally published in the Sci & Tech section of The Statesman on 8th Day on 15 October, 2006.

Cure for Blood, Breast and Cervical Cancers

Researchers from Kolkata’s Chittaranjan National Cancer Institute have found two plants frequently used in Ayurvedic medicines effectively battle out four types of cancer in lab.

They discovered the root extract of Tiliacora racemosa (Tiliacoru) and the nut oil of Semecarpus anacardium (Dhobi nut) eliminated cultured human tumour cells from acute myeloblastic (myeloblast is a bone marrow cell) leukaemia, chronic myelogenic (associated with bone marrow) leukaemia, breast and cervical cancers.

“The herbal preparations from T racemosa and S anacardium selectively force cancer cells to commit suicide, sparing healthy neighbouring cells,” claims Madhumita Roy, who headed the team of researchers.

“The anti-cancer active compounds identified in the root extract of T racemosa are a number of bisbenzyl isoquinoline alkaloids, a type of organic compound and phenolic substances, also organic compounds, in the nut oil of S anacardium,” writes the researcher in a recent issue of the journal Phytotherapy Research (Vol 18, No 8).

“The findings of the research are indicative of a potential therapeutic role of these herbal preparations in human cancer,” says co-author Sutapa Chakraborty.

To study the anti-cancer effects of the plant extracts, the team produced an ethanol (alcohol) extract of T racemosa root (TA), an alkaloid-containing root extract of T racemosa (TR) and extracted the S anacardium nut oil (SO) using Ayurvedic principles. When tumour cells were exposed to these extracts, TA annihilated all the four types of cancer cells. TR and SO only caused the demise of leukaemic cells while breast cancer cells’ growth was partially inhibited by so and TR.

The above article was written by this blogger and originally published in ‘Down To Earth’, a science and environment fortnightly from New Delhi on 28 Feb’ 2005.

Herbal cure for snakebite

A TEAM from Kolkata-based Indian Institute of Chemical Biology and University of Calcutta have found that the seed extract of Strychnos nux vomica (SNV) — an Indian herb — could neutralise the toxins present in the venom of viper (Daboia russelii) and cobra (Naja kaouthia). The researchers isolated the active compound from the seed extract and found that it protected animals against the toxic effects of the venom. “The active compound, probably a organic compound, may lead to the development of a herbal drug more effective than snake venom antiserum (serum with antibodies against snake venom),” says Antony Gomes, the lead author. “We think that it works by inactivating the toxic enzymes of the venom,” he adds. The findings of their research are published in a recent issue of Indian Journal of Experimental Biology (Vol 42, No 5).

The venom contains a host of lethal enzymes that wreak havoc on healthy cells. Viper venom leads to excessive bleeding and build-up of abnormal body fluid. Cobra venom cripples cardiac muscles and nerve cells. After preparing the seed extract of SNV, Gomes and his colleagues measured the lethal dose (in other words that killed lab mice) by injecting the venom of viper and cobra into the tail vein of male mice. The lethal doses for viper and cobra venom were found to be 2.4 microgrammes and 3.09 microgrammes respectively. The extract even neutralised the adverse affects in guinea pigs and rats. The team also found that a combination of antiserum and seed extract was more potent against venom than antiserum alone.

The above article was written by this blogger and originally published in 'Down To Earth, a science and environment fortnightly published from New Delhi on 15 Nov'2004

Sixth Extinction: Will it be man-made?

The entire basis of organic evolution is underpinned by the appearance of some species and the disappearance of others; extinction is therefore a natural process.

According to the fossil record, as few as 2-4% of the species that have ever lived are believed to survive today. The remainders are extinct, the vast majority having disappeared long before the arrival of humans.

But, the rapid loss of species that we are witnessing today is estimated by some experts to be between 100 and 1,000 times higher than the “background” or expected natural extinction rate.

Unlike the mass-extinction events of geological history, the current extinction phenomenon is one for which a single species - ours - appears to be almost wholly responsible. Such a deteriorating situation is being referred to as “the sixth extinction crisis”, after the five known extinction waves in the Ordovican, Devonian, Permian, Triassic and Cretaceous Periods.

Man-made Prehistoric Extinction
Extinctions caused by humans are generally considered to be a recent, modern phenomenon. However, humanity's first significant contribution to the rate of global extinction may have occurred during the past 100,000 years, when North
and South America and Australia lost 74 to 86% of the genera of "megafauna" - mammals greater than 44 kg.

In Australia, where the earliest human remains are dated to approximately 64,000 years, the great majority of the 22 identified genera of large land animals disappeared between 30,000 and 60,000 years ago.

In the Americas, almost 80% of large-bodied genera became extinct. Extraordinary creatures, such as sabre-toothed cats, mammoths, giant armored glyptodonts and giant ground-sloths, all disappeared some time between 11,000 and 13,000 years ago, coinciding with the dates of the first clear evidence of a human presence there.

Recent Extinction
Island megafaunas - like giant birds known as moas in New Zealand, the dodo on Mauritius, giant lemurs and the extraordinary elephant bird in Madagascar, or large rodents and ground-sloths in the Caribbean - survived until much more recently than the continental faunas. All seem to have disappeared within a few hundred years after the arrival of humans - in the case of the moas within the last 300 years.

In the last 500 years, human activity has forced 844 species to extinction (or extinction in the wild).


Current Status

A total of 15,589 species of plants and animals are known to face a high risk of extinction in the near future, in almost all cases as a result of human activities. This includes 32% of amphibian species, 24% of mammal species, 12% of bird species, 25% of conifers and 52% of cycads.

Of the 129 recorded bird extinctions, 103 are known to have occurred since 1800, indicating an extinction rate 50 times that of the background rate.

The total number of threatened animal species has increased from 5,205 to 7,266 since 1996.

Habitat loss and degradation affect 86% of all threatened birds, 86% of mammals, and 88% of threatened amphibians.

Main Culprit Countries
Indonesia, India, Brazil and China are among the countries with the most threatened mammals and birds, while plant species are declining rapidly in South and Central America, Central and West Africa, and Southeast Asia.

Ballooning Urbanisation

In 1800 only about 2 percent of the world's population lived in urban areas. In only 200 years, the world's urban population has grown from 2 percent to nearly 50 percent of all people. At the beginning of the 20th century some 250 million people lived in cities – only about 15 per cent of the world’s population. At the end of century, nearly half of the 6000 million people on the planet lived in urban areas.

The most striking examples of the urbanization of the world are the megacities of 10 million or more people. In 1975 only four megacities existed; in 2000 there were 18. And by 2015 the UN estimates that there will be 22.

Overexploitation: The Culprit Homo sapiens

Exploitation, including hunting, collecting, fisheries and fisheries by-catch, and the impacts of trade in species and species' parts, constitutes a major threat for birds (30% of threatened birds), mammals (33% of threatened mammals), amphibians (6% of threatened amphibians), reptiles and marine fishes.

International Trade

Many animals and plants are increasingly threatened because of international trade in wildlife and wildlife products. In some cases (pets, rare plants) the living organism is in demand; in other cases, specific body parts like skins, furs, bones, ivory, sex organs, bile, skeletons, and claws are highly valued for ornaments, jewelry, or for putative medicinal or aphrodisiac qualities

These are mostly luxury items in demand in industrialized countries, by consumers that have very little knowledge of how endangered some of these animals are. International wildlife trade has grown and become very profitable with increased prosperity, improvements in shipping and fast air transport.

The major exporters are tropical and subtropical countries of Africa, Southeast Asia and South America (see chart) while the major importers are Europe, Japan and the U.S.

The U.S. is both an exporter and importer and is the largest market in the world for these items, importing and exporting about $1 billion worth of wildlife and wildlife products each year (out of a total world trade of $5 billion).


Three of the eight species of tiger are already extinct and all the others are threatened because of a combination of habitat loss and poaching for the Asian traditional medicine market. The total tiger population has declined by 95% in the 20th century, leaving only about 5,000. The Siberian tiger, with only 200 animals, could be extinct within a few years if China does not take effective measures immediately.