Where can I find any good article about drugs derived from natural product. I've already search through the internet but I couldn't find any specific article.

Drug Discovery From Natural Sources
Young-Won Chin, Marcy J. Balunas , Hee Byung Chai , and A. Douglas Kinghorn

ABSTRACT
Organic compounds from terrestrial and marine organisms
have extensive past and present use in the treatment of many
diseases and serve as compounds of interest both in their natural form and as templates for synthetic modifi cation. Over 20 new drugs launched on the market between 2000 and 2005, originating from terrestrial plants, terrestrial microorganisms, marine organisms, and terrestrial vertebrates and invertebrates, are described. These approved substances, representative of very wide chemical diversity, together with several other natural products or their analogs undergoing clinical trials, continue to demonstrate the importance of compounds from natural sources in modern drug discovery efforts.

Link: http://www.aapsj.org/articles/aapsj0802/aapsj080228/aapsj080228.pdf

Here is another review article I came across.

The Value of Plants Used in Traditional Medicine for Drug Discovery
Daniel S. Fabricant and Norman R. Farnsworth

VOLUME 109 | SUPPLEMENT 1 | March 2001 Environmental Health Perspectives

Abstract
In this review we describe and discuss several approaches to selecting higher plants as candidates for drug development with the greatest possibility of success. We emphasize the role of information derived from various systems of traditional medicine (ethnomedicine) and its utility for drug discovery purposes. We have identified 122 compounds of defined structure, obtained from only 94 species of plants, that are used globally as drugs and demonstrate that 80% of these have had an ethnomedical use identical or related to the current use of the active elements of the plant. We identify and discuss advantages and disadvantages of using plants as starting points for drug development, specifically those used in traditional medicine.

Link: http://www.ehponline.org/members/2001/suppl-1/pdf/fabricant.pdf