The Human Immunodeficiency Virus (HIV) is quickly becoming one of the world’s deadliest viruses and it is currently the most significant infectious pathogen with devastating consequences Plants have something to offer for its cure.
The Human Immunodeficiency Virus (HIV) is quickly becoming one of the world’s deadliest viruses and it is currently the most significant infectious pathogen with devastating consequences. Since the description of HIV as the causative agent of the acquired immunodeficiency syndrome (AIDS), HIV has produced a worldwide pandemic. According to the recent report of UNAIDS and WHO, in Dec. 2007, over 6800 person become infected with HIV and over 5700 persons die from AIDS everyday, and besides millions of people are living with HIV infection world wide. The spread of HIV worldwide from the year 1990 to 2007 is shown in figure 1.1 (Fig. 1.1 and Table-1.1). The total estimated number of people newly infected every year with HIV globally from 1990 to 2007 are shown in the figure 1.2 (Table-1.2 and Fig. 1.2 ) Continent wise data of adult and children estimated to be living with HIV globally number 33.2 million [30.6-36.1 million] in the year of 2007 (Fig. 1.3 and Table- 1.3). (UNAIDS and WHO, 2007), and Figure- 1.4 shows globally estimated number of adult and child death due to AIDS since 1990 to 2007. This shows a reduction of 16% compared to the estimate published in 2006 (39.5 million [34.7-47.1]), (UNAIDS/WHO, 2006). The single biggest reason for this reduction was the intensive exercise to assess India’s HIV epidemic, which resulted in a major revision of that country’s estimates. Important revision of estimates elsewhere, particularly in sub-Saharan Africa, also contributed. Of the total difference in the estimates published in 2006 and 2007, 70% are due to changes in six countries: Angola, India, Kenya, Mozambique, Nigeria, and Zimbabwe. In addition, India has expanded its HIV sentinel surveillance system in the recent years and the number sites increased from 155 in 1998 to 1120 in 2006. Data from pregnant women attending antenatal clinic, people attending sexually transmitted infections clinics and population groups that are higher risk of exposure to HIV are included in the surveillance.
Prevalence trend in India vary greatly between states and regions. Even in the four southern states (Andhra Pradesh, Karnataka, Maharashtra and Tamil Nadu) where the large majority of people living with HIV are residing , HIV prevalence varies and the epidemic tends to be concentrated in certain districts (NACO, 2005; World Bank, 2005). Reported adult HIV prevalence in six states included in the recent national population-based survey varied from 0.07% in Utter Pradesh, to 0.34% in Tamil Nadu, 0.62% in Maharashtra, 0.69% in Karnataka, 0.97% in Andhra Pradesh, and 1.23% in Manipur (Fig. 1.5). Prevalence in all other states together was 0.13%. An earlier analysis of sentinel surveillance data also showed that overall HIV prevalence in southern states was about five times higher than in northern states in 2000-2004 ( Kumar, et al., 2006). Out of 33.2 million people living with HIV, 2.5 million people more newly infected with HIV and about 2.1 million died worldwide (table 1.1).
Several studies shows the use of Plants as folk remedies and ethnobotanical literature has described the usage of plant extracts, infusions and powders for centuries for diseases now known to be of viral origin (Suckling, 1991). There is an increasing need for search of new compounds with antiviral activity, as the treatment of viral infections with the available antiviral drugs is, often unsatisfactory due to the problem of viral resistance coupled with the problem of viral latency and conflicting efficacy in recurrent infection in immunocompromised patients.
Ethnopharmacology provides an alternative approach for the discovery of antiviral agents, namely the study of medicinal plants with a history of traditional use as a potential source of substances with significant pharmacological and biological activities (Kapoor, 1990; Dev, 1999). The Indian subcontinent is endowed with rich and diverse local health traditions, which is equally matched with rich and diverse plant genetic source. A detailed investigation and documentation of plants used in local health traditions and ethnopharmacological evaluation to verify their efficacy and safety can lead to the development of invaluable herbal drugs or isolation of compounds of therapeutic value.
A number of compounds extracted from various species of higher plants have shown antiviral activity. Samples included tannins, flavones, alkaloids, that displayed in vitro activity against numerous viruses. It has been suggested that selection of plants on the basis of ethnomedical considerations gives a higher hit rate than screening programmes of general synthetic products. Bacopa monneri has been used in conditions like epilepsy, insanity, nervous disorders, Hypercicum hookerianum in anxiety and inflammation, in China medicinal herb Tian-Hua-Fen (Trichosanthes kirilowii) used to reset menstruation and expel retained placentas (Collins et al., 1997), Usnea complanta and Tagetes minuta are used for bacterial infections, Santolina chamaecyparissus as a stimulant, vermifuge and a stomachic. A number of plant extracts reported in traditional medicine have antiinfective properties and have also been screened for antiviral activity including HIV.
Notwithstanding the evidence that all the billions of dollars of NIH funded AIDS research has netted neither a drug cure nor one causal factor, such as a virus, remarkable improved results come in the treatment of the symptoms of AIDS and enhancement of HIV positive patients by Ayurvedic system of medication.
The science of life in India is Ayurveda. Ayu, a Sanskrit term, means life, and veda means knowledge, or science. Ayurveda views health as an unlimited composite of all of the features of life. Human life is not seen as separate from its environment, even cosmically. So, Ayurvedic practitioners incorporate all aspects of healing into their practices: Herbs, foods, physical therapies such as massage, oils, spirituality and even modern medicine. Ayurvedic professionals look for balance in the body and mind.
Sudhir Borgonha, an Indian physician writing for a South Indian publication titled Family Health (Scott, 2006), summarizes scanty reports and anecdotes circulating mostly in small Indian periodicals, weeklys, monthlys and even in the Times of India, about T.A. Majeed, an Ayurvedic pharmacist formulated a combination of herbs, largely by "chance" that has been directly associated with healing of AIDS-related syndrome. Majeed formula boosts immune system of human, and called it ImmunoQR. Enter Chitra Soman. Chitra, a college student had unknowingly married (an arranged marriage) an AIDS patient who died a year after the wedding. Just three days after his death, Chitra gave birth on March 9, 1992 to his baby girl. Both Chitra and the girl were HIV positive, and suddenly became social outcasts. Chitra refused Majeed's offer of the ImmunoQR compound because he was not a doctor. Majeed then met with an HIV positive patient named Baburaj, who had been in the news. Baburaj agreed to take the medicine. Within fifteen days Baburaj wrote to Majeed to tell him that he felt better and was gaining weight. Majeed forwarded the letter to Chitra, who then agreed to take a course of treatment. Chitra was tested to be HIV negative on October 31, 1992. Baburaj was pronounced HIV negative on October 16th, 1992. Majeed had given his formula to over 2,000 patients as of February, 1995. "Excepting a few," he said to The Statesman, of New Delhi, "all have been cured." He stated that, as in the cases with Chitra and Baburaj, it takes about fifty days of treatment, and the patient fully recovers. After ninety days the patient is normal. He also commented that no medical authorities or hospitals will give Chitra or other patients a certificate proving them to be HIV negative. "[They are] not willing," he stated, "to accept that someone from an ancient system of medicine has found a cure to the deadly virus, whereas they have failed despite years of research. But some of these allopaths have been sending their friends and relatives to me for the medicine privately." So these evidences show the great potential of our Ayurvedic medication system (Scott, 2006)
Same type of preparations also used in Chinese traditional herbal system for curing diseases including AIDS, medicinal herbs are being used in the treatment of HIV positive subjects and AIDS patients. One example is the traditional Chinese medicinal herb Tian-Hua-Fen (Trichosanthes kirilowii), which appears in the classical Chinese medical reference work Compendium of Materia Medica from the late 14th century. Tian-Hua-Fen has been used in China for hundreds of years to reset menstruation and expel retained placentas. Trichosanthin (TCS), an active protein component isolated from Tian-Hua-Fen, has been shown to inhibit HIV infection and has been used in the clinical treatment of AIDS (Zhao et al., 1999).
For exploring natural product to cure HIV infected patients Gene products required for viral replication are suitable targets for fighting the disease. Currently, the most successful drugs target reverse transcription, an essential process to HIV infection. Other drugs inhibit the activity of HIV protease, an enzyme required for maturation of building blocks to assemble new virus particles. The HIV protease is a virally encoded protease that serves to cleave the ‘‘gag’’ and ‘‘gag-pol’’ polyprotein precursor into mature, functional proteins. The ‘‘gag’’ gene codes for structural proteins that form the shell around the viral RNA. The ‘‘pol’’ gene codes for enzymes such as reverse transcriptase, RNAase H or integrase and HIV protease as well. Among the approaches to develop, anti-HIV drugs those directed against the HIV-protease seem to be the most promising. The HIV-protease inhibitors developed so far are substrate-based and function at the active site. Most of them are peptide mimetic compounds based on the substrates primary sequence. Indinavir is among the most extended inhibitors of HIV-protease used nowadays in therapy against HIV infection. However severe side effects, associated with this drug have been described, such as fat accumulation, hepatitis, kidney stone formation or cutaneous side effects. These negative effects, but especially the high rate of mutation of the virus, that generates new strains resistant to known inhibitors and cross resistance as well, have promoted the search for new HIV enzyme inhibitors (Jacobsen et al., 1995; Ridky and Leis, 1995; Brillant, et al., 2004 ). There are several reports of HIV protease inhibitors from natural sources, such as microbial alkaline protease inhibitor and lignin-like substances derived from an edible mushroom and from many other natural products. Traditional plants have also been screened against HIV-Protease as a part of anti-HIV drugs.
One of the characteristic feature of HIV is high degree of variability of its genome among independent virus isolates. This feature impacts many aspects of the biology of HIV, including tissue and targets cell specificity, clinical spectrum and pathogenesis, geographic and temporal distribution of virus, susceptibility of antiretrovirals, and prospects of developing an effective cross-reactive vaccine. Secondly, infection with HIV sooner or later, creates a window for the infection with other microbes, which were hitherto contained by the immune system, to become progressive. Added to this is the concern that weakened human immune systems may become favorable environments for the adaptation of traditionally non-human infectious agents. Most importantly, there has been a fervent and continuous search for preventive and curative therapeutics in an effort to stem the spread of the pandemic. The efficacies of clinically available HIV enzymes and fusion inhibitors have been limited by the selection and development of resistant variants, appreciable levels of toxicity and the absence of a curative effect. As a consequence, the search for better anti-HIV agents continues. Alongside, the endeavors in designing HIV antagonists based on the structure, catalytic properties of its enzymes, and surface receptors, alternative approaches such as the search for secondary metabolites from plant species capable of arresting viral replication are being pursued.
A number of laboratories are actively involved in the development of antiviral agents that interfere with HIV at different stages of viral replication. However, the rapid spread of the AIDS epidemic and the appearance of HIV strains resistant to the currently available drugs suggest that effective and durable chemotherapy of this disease will require the use of innovative combinations of drugs having diverse mechanisms of anti-HIV activity. For this reason, there is a continuous need for alternative inhibitors. New chemical entities with such activities may be identified through a variety of approaches, one of them being screening of natural products. Over the last decade, antiviral researchers have also turned to many of the traditional folk medicines, invariably a ‘cocktail’ of natural products, to uncover the scientific basis of their remedial effects. Recently a reported plant-derived anti-HIV compound, which serves to underline the fact that selected medicinal plants with HIV-inhibitory activity, is widely distributed in nature. Natural products can be selected for biological screening based on ethnomedical use, random collection or a chemotaxonomic approach (i.e. screening of species of the same botanical family for similar compounds). Comparison of the different approaches showed the selection method based on folklore to give a higher percentage of active leads, although, in some cases, the same active compounds were isolated from botanically non-related active plants. It thus seems more probable to find demonstrable biological activity among plants with recorded medicinal uses than among those selected at random.
The positive impact of current anti-HIV treatments in decreasing the rate of AIDS progression and death among people living with HIV is undeniable. However, several studies show that even in patients with undetectable plasma viremia (<50 copies/ml), virus rebounds after the interruption of Highly Active Antiretroviral Therapy (HAART) due to the presence of pockets or reservoirs of latently infected cells. It is now clear that HAART alone cannot cure HIV. And since the long-term use of HAART is associated with metabolic disorders and toxicities, the identification of new anti-HIV agents with novel mechanisms of action is an important therapeutic goal (Pontesilli et al., 1998).
Today most researchers seem to lie on the glass-is-half-empty side on the question of HIV eradication. But that wasn't always the case. Talk about wiping out HIV infection was more popular in the late 1990s when powerful combinations of antiretroviral (ARV) drugs- highly active antiretroviral therapy (HAART)—first became available and were bringing some people with AIDS back from the brink. Where drugs were available, the death toll of the disease plummeted and the level of virus in the blood of infected people dropped below detection limits of conventional assays of the time, about 500 HIV-RNA copies/ml blood (Bernard, 2004).
Even so, it was clear that drugs could only attack actively replicating virus. They could not touch another potential source of HIV—copies integrated into the chromosomes of resting CD4+ memory T cells. By their nature, these cells could be long-lived and the fear was that if the drugs were eventually withdrawn, some antigen would reactivate these cells and release the latent virus. But David Ho at the Aaron Diamond AIDS Research Center in New York and his colleagues calculated that if viral replication was completely stopped then existing latent cells harboring HIV could die off in less than three years.
HIV protease is one of the translated products from the HIV structural protein pol gene. This retroviral protease specifically cleaves other structural polypeptides at discrete sites to release these newly activated structural proteins and enzymes, thereby rendering the virion replication-competent. As such, inhibition of the HIV protease by potent compounds may prevent proviral integration of infected T-lymphocytes during the early phase of the HIV-1 life cycle, as well as inhibit viral proteolytic processing during its late stage. Additionally, the protease inhibitors may have the advantages of being more readily available, longer lived in virus, and less toxic than currently available drugs, possibly due to their specificity for the retroviral protease (Erickson, 1993.). Several pharma companies launched worldwide related inhibitors of HIV proteases - e.g., U.S. Pat. No. 5,962,640, U.S. Pat. No. 5,932,550, Australian Patent No. 705193, Canadian Patent Application No. 2,179,935, European Patent Application No. 0 751 145, and Japanese Patent Application No. 10087489.
On-going treatment of HIV- infected individuals with compounds that inhibit HIV protease has led to the development of mutant viruses that possess protesases that are resistant to the inhibitory effect of these compounds (Flexner, 1998.). Thus, to be effective, new HIV protease inhibitors must be effective not only against wild-type strains of HIV, but must also demonstrate efficacy against the newly emerging mutant strains that are resistant to the commercially available protease inhibitors. Accordingly, there continues to be a need for new inhibitors targeting the HIV protease in both wild type and mutant strains of HIV.
In view of the above facts, the present study has been carried out with the following objectives:-
Litrature survey of AIDS epidemic, causative agent HIV, its life cycle, available chemotherapy, its shortcoming, future chemotherapeutic target for new anti- HIV agents.
Ethnopharmacological study of plant products, potency of plants in curing AIDS.
Ethnobotanical survey of traditionally used medicinal plants in some districts of western U.P., southwest Uttaranchal states, and Jaipur of Rajasthan state.
To study different assay system using aqueous and organic extracts preparation to check out anti-HIV activity of selected plant extracts.
Different assay systems employing aqeous and organic extracts to test with anti-HIV activity of selected plants.
Enzymatic assay - screening the anti-HIV agents of plant origin using pepsin assay and HIV-Protease assay.on selected plants.
Biochemical analysis was performed of active plant extracts.