Preface [Hot Topic: Advances in the Studies of Anti-HIV Drugs-Part I (Guest Editor: S.P. Gupta)]

In the present era, acquired immunodeficiency syndrome (AIDS) is the most fatal disorder for which no completely successful chemotherapy could be developed so far. The pandemic spread of this disease has prompted an unprecedented scientific and clinical effort to understand and combat it. The causative agent of AIDS has been identified as a retrovirus of type 1 (HIV-1). Therefore, a great attention has been focused in the recent years on the design and development of anti-HIV drugs and we consequently decided to bring out a hot topic issue on the subject with the title: Advances in the Studies of Anti-HIV Drugs. Owing to a good response from authors, two successive issues had to be devoted as Part I and Part II of the topic. The replicative cycle of HIV-1 presents several viable targets that could be exploited for this purpose. The present issue, as Part I, covers 6 articles, in which the very first article by José A. Esté hits at the virus entry itself into the host cell and reviews the current state of HIV entry inhibitors, their mechanism of action, and their therapeutic value against HIV infection and AIDS. In recent years, tremendous progress has been made in understanding the HIV-1 entry process in which the viral and cellular membranes are fused, resulting in the subsequent delivery of the viral genome into the host cell. The mechanistic insight gained from these studies has led to the formulation of fusion inhibitors. The second article by Baldwin et al. addresses this rapidly developing area of HIV research with a focus on the mechanistic role of fusion inhibitors targeted to the HIV-1 gp41 transmembrane glycoprotein. The process of reverse transcription of genomic RNA into double-stranded DNA is central to the replication of HIV and this process requires the enzyme reverse transcriptase (RT). Therefore, the initial development of anti-HIV drugs was largely based on RT inhibitors, which is still sustaining enough interest of the researchers. Articles 3 and 4, therefore, address some rational bases of designing potential RT inhibitors. While in article 3, Mager discusses an excellent predictive model based on hybrid canonical-correlation neural network (HCCNN) approach for the development of RT inhibitors, in article 4, Pungpo et al. present a Hologram quantitative structure-activity relationships (HQSAR) study that yields another excellent predictive model. The cleavage of large polypeptide precursors into smaller, functional protein fragments, required for packaging and infectivity of budding virions, needs HIV protease. Hence, the studies on HIV-1 protease inhibitors have also been immensely carried out. The fifth article by Kurup et al. discusses the QSARs of several classes of HIV-1 protease inhibitors, pointing out the important physicochemical, electronic, and steric properties of the molecules that govern their activity. The last article by Sriram and Yogeeswari presents the design and development of agents that have broad spectrum of chemotherapeutic properties that may be more effective in the treatment of HIV-1 infection or AIDS. In recent years, isatinimino compounds, which these authors discuss, have been reported to exhibit a broad spectrum of chemotherapeutic properties that include anti-HIV, antituberculous, antifungal and antibacterial activities. I thank all the authors of this part for their excellent stimulating contributions and hope that the readers will greatly enjoy reading them as I did and that these contributions will be of great value to those involved in research in this area.