Saturday, June 30, 2007

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.

Friday, June 29, 2007

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