Anti-HIV natural products

Acquired immunodeficiency syndrome (AIDS), caused by human immunodeficiency virus (HIV), is an immuno- suppressive disease that results in life -threatening oppor- tunistic infections and malignancies. Despite continuous advances made in antiretrovira l therapy, AIDS has become the leading cause of death in Africa and fourth worldwide; the number of people with HIV is increasing at an alarming rate in India and Southeast Asia. Biodiversity of the plant kingdom has always provided a source of new drug candidates for almost all disease areas. The number of compounds exhibiting anti-HIV activity and isolated from natural sources is increasing steadily. Calanolide A, a coumarin isolated from Callophyllum lanigerum and two other natural product-derived molecules, DSB and 3-hydroxymethyl- 4-methyl DCK are phase II clinical candidates, with potential to come up as drugs for treatment of HIV i nfec- tion. Here, the natural products possessing anti-HIV activity have been discussed, with main focus on recent outcomes from natural sources as anti-HIV agents. ACQUIRED immunodeficiency syndrome (AIDS) is a clinical syndrome that is the result of infection with human i mmuno- deficiency virus (HIV), which causes profound i mmuno- suppression. It has been a serious, life -threatening health problem since the first case was identified in 1981 and is the most quickly spreading disease of the century. Since the epidemic began, more than 60 million people have been infected with the virus. HIV/AIDS is now the leading cause of death in Sub-Saharan Africa. Worldwide, it is the fourth biggest killer. According to recent reports of WHO and UNAIDS, at the end of 2004, an estimated 40 million people (37.2 million adults and 2.2 million children) globally were living with HIV, out of which about 22 million had died. The most affected is Sub-Saharan Africa, where 3.1 million adults and children became infected with HIV during the year 2004 and 2.3 million died in 2004. By the end of 2004, the total number of people living with HIV/ AIDS in the region has reached 25.4 million 1 . Around 1.2 million people in Asia acquired HIV in 2004, bringing the number of people living with HIV to an estimated 8.2 million. A further 540,000 people are estimated to have died of AIDS in 2004. The spread of HIV in India has been di- verse, with much of India having a low rate of infection and the epidemic being most extreme in the southern states. As of December 2004, 92% of all nationally reported AIDS cases has been found in 10 of the 28 states and 7 union territories. The greatest numbers were in Maharashtra and Gujarat in the west; Tamil Nadu and Andhra Pradesh in the south; and Manipur in the Northeast. In the southern states, the infections are mostly due to heterosexual contact, while infections are mainly found amongst injecting drug- users in Manipur and Nagaland. The maximum number of AIDS cases has been reported in Tamil Nadu (44,492) followed by Maharashtra (12,783) out of 96,978 AIDS cases in year 2004. A very high proportion of men and women infected with HIV virus are in their active reproductive ages and around half of the people who acquire HIV become infected before they turn 25. Of greater concern is the possibility of infected mothers transferring the disease to their babies