The comprehensive study, suggested by the Singapore-based authors to be the first of its kind, assessed 124 natural product combinations.
Writing in PLoS One, the researchers report that certain combinations of natural products such as those used in traditional Chinese medicine are as potent as made-made drugs designed specifically to battle the condition.However the team, led by Professor Chen Yu Zong from the National University of Singapore andrevealed that the odds of finding an effective combination of natural products are very low.
Chen and his colleagues said, for example, that their findings show how the active ingredients in combinations of natural products can achieve the same level of potency as synthetic anticancer and antibacterial drugs, however these products must be taken in larger quantities or for a longer period of time.
“There have been claims that natural products simply have a placebo effect,” said Chen. “In our study, we looked at more than 100 types of natural product combinations that are perceived to be the best and found that it is possible for natural products to achieve the same effectiveness as man-made drugs.”
“However, the probability of finding such combinations based on traditional methods is low (below 3%) as the natural products have to be of sufficient potency and taken in the right combination."
The research team noted that while combinations of natural products have been extensively studied and are widely used in traditional Chinese, folk and alternative medicines, there are still many questions on whether there is any true therapeutic value in such products, or whether any benefits are merely placebo.
“The important questions are whether synergistic effects can sufficiently elevate therapeutic potencies to drug levels, and by what mechanisms and at what odds such combinations can be assembled,” said the researchers.
Chen and his team analysed data from 1,601 previous research papers. This literature reported on the cell-based potencies of 190 approved anticancer and antimicrobial drugs, 1378 anticancer and antimicrobial natural products, 99 natural product extracts, 124 synergistic natural product combinations, and 122 molecular interaction profiles of the 19 natural product combinations with collective potency enhanced to drug level or by more than 10-fold.
They found natural products are generally 10 to 100 times weaker than man-made drugs, but noted that many lower potency natural products can be assembled into combinations of drug level potency.
However, they said the probability of these combinations achieving the same therapeutic effect as a drug – when issues such as bioavailability and the ability to target the right set of regulators or effectors within cellular systems are considered – is low
Chen and his team said their findings now provide a foundation for further studies on the clinical effectiveness of herbal medicine, and may lead to research in to how to best achieve combinations of natural products and synthetic drugs can be taken together to fight diseases.
The team said they will continue to conduct more research in this area, in particular, to determine how to achieve the same level of effectiveness for natural products as synthetic drugs – with a focus on popular herbal products and frequently prescribed traditional medicine.
Published online ahead of print, doi: 10.1371/journal.pone.0049969
“What does it take to synergistically combine sub-potent natural products into drug-level potent combinations?”
Authors: Qin C, Tan KL, Zhang CL, Tan CY, Chen YZ, Jiang YY.