| The studies that have been conducted to investigate the effects of Chinese
herbs on HIV-1 activity can be divided into two large categories: laboratory and
clinical.
Laboratory Studies.
Laboratory studies primarily deal with elucidating a possible anti-HIV
mechanism of Chinese herbs. The typical sequence of laboratory
investigation involves using various lab techniques to 1) screen large numbers
of herb extracts for possible anti-HIV activity, 2) isolate those herbs which
show the highest anti-HIV activity on the initial screen (so-called "lead
compounds") and 3)analyze the lead compound for the active anti-HIV component.
The are many laboratory studies on Chinese herbs out there. Part of
the reason for the multitude of trials are 1) the number of Chinese herbs to
screen (thousands), 2) the different techniques used to screen them (different lab
techniques have different limitations and advantages: some techniques look for
anti-HIV activity in general, some can only look for inhibition of certain steps in the
HIV life-cycle only, and finally 3) there are multiple steps in the HIV life-cycle
that can be targeted by drugs/herbs, including
- viral adsorption to the cell membrane
- fusion between the viral envelope and the cell membrane
- uncoating of the viral nucleocapsid
- reverse transcription of the viral RNA to proviral DNA
- integration of the proviral DNA to the cellular genome
- DNA replication
- transcription of the proviral DNA to RNA
- translation of the viral precursor mRNA to mature mRNA
- maturation of the viral precursor proteins by porteolysis,
myristoylation, and glycosylation
- budding, virion assembly and release
Newer techniques for improving lab studies are always on the horizon.
For instance, computer molecular modeling has recently been brought to bear on
Chinese herb research, in which it is primarily useful as a way to accelerate the
screening step of the sequence.11But even
with improvements such as these, the reader can get an
idea of why there are some many studies done (and so many more to still do) when
considering the reasons listed above. Rather than make a long list of
studies to overwhelm readers, there is a link below to some
of the most recent lab research on various Chinese herbs. Look for the
classic steps outlined above while reading through these studies (1. screening,
2. isolation, and 3. analysis of "lead compounds").
Click here for exciting new Laboratory Research
Clinical Studies
In contrast to the large number of laboratory studies, there is a paucity of
clinic research within the domain of herbal medicine and AIDS/HIV. Clinical studies attempt
to discover if Chinese herbs, regardless of what is shown in the lab, actually
result in some benefit in human beings with AIDS. The distinction is an
important one, as it is possible for a drug (or herb) to show promise in the
laboratory, but not show any benefit when studied in humans. This
discrepancy can result for several reasons: uses of dosages in the lab that are
unattainable in human tissue, for reasons of adverse effects or different modes
of delivery; unforeseen interaction with human physiology; unforeseen
interaction with other drugs that the patient must take; etc. Most of the
studies on Chinese herbs is laboratory research; however, they are many such
studies and several are very compelling works that warrant further
investigation. As with laboratory studies, there are several variables in
clinical research that result in many types of studies. Clinical studies
can be Phase I, II, or III, can be
retrospective or prospective, have different
exclusion and inclusion criteria, need to be evaluated for internal and external
variability, and have different endpoints. These are all characteristics
of a clinical study that one should pay attention to as they read it.
Click here for the latest on Clinical Research |
