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A Pill for HIV

Dried sea cucumbers in a Chinese pharmacyImage via Wikipedia

Indian scientists have identified a chemical in sea cucumbers that may protect against unwanted pregnancy as well as HIV.

The next generation of spermicides to help women in birth control may contain a compound extracted from sea cucumbers found in the Andaman Sea. A team of researchers from the Central Drug Research Institute (CDRI) in Lucknow has found that the foot-long, cylindrical sea cucumber, called semper, has abundant quantities of a compound that may be more effective and safer than nonoxynol-9 (N-9), a key-ingredient of all major over-the-counter birth control products available in the market today.

N-9 has been in the dock for a while now as scientists elsewhere have found that though it is a very effective spermicide, it offers limited or no protection against HIV and other sexually transmitted diseases. This is because N-9 — which is also used in detergents and several cleaning and cosmetic products — has a strong detergent action leading to the destruction of lactobacilli, which has a protective function, in the vagina.

The compound that the CDRI scientists extracted from semper, of the Bohadschia vitiensis family, is actually a part of the marine organism’s defence system against potential predators. The compound, bivittoside-D, is contained in the white filaments that sea cucumbers release when they feel threatened. These white filaments, called Cuvierian tubules, are of high adhesive and tensile strength which helps immobilise the predators.

The molecular studies of the compound have been reported by the scientists in the latest issue of Archives of Medical Research. They have also reported that in lab studies the extract killed 100 per cent of the sperms in less than 20 seconds. Besides, it didn’t have any adverse effect on the friendly lactobacilli.

CDRI scientist Vijai Lakshmi, who led the team, says that bivittoside-D — which belongs to a class of chemicals called saponins — can offer protection against HIV because it eliminates the favourable conditions that HIV exploits to enter a human system. These favourable conditions are provided by lipid rafts, tiny regions in the cell membrane which are filled with cholesterol. Interestingly, these lipid rafts are vital for the survival of sperms post-coitus. Saponins, on the other hand, form complexes with cholesterol, ensuring that the lipid rafts are not available to both HIV and the sperm.

Though more studies are required, the scientists hope that bivittoside-D — with its irreversibly immobilising capacity — may emerge as a possible replacement for N-9.

Sources: The Telegraph (Kolkata, India)

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