Asis Bhaumik

Bio: Asis Bhaumik is an academic researcher from University of Calcutta. The author has contributed to research in topics: Diosgenin & Dendrobium fimbriatum. The author has an hindex of 3, co-authored 4 publications receiving 37 citations.

Echinulin, a Novel Cyclic Dipeptide Carrying a Triprenylated Indole Moiety from an Anacardiaceae, a Cucurbitaceae and Two Orchidaceae Plants: Detailed High Resolution 2D-NMR and Mass Spectral Studies.

Abstract: A levorotatory compound, C 2 9 H 3 9 N 3 O 2 was isolated from the edible fruits of Rhus parviflora (Anacardiaceae) along with citric acid 2-methyl ester. A detailed 1 H and 1 3 C NMR spectral studies including 1 H- 1 H correlation, long range 1 3 C- 1 H correlation (HMBC and HMQC) and also NOESY confirmed its structure as 3S,6S,3-[[2-(1,1-dimethylallyl)-5,7-bis(3,3-dimethylallyl-1H-indo-3-yl[methyl]-6-methyl-2,5-piperazinedione (1) and allowed the unambiguous assignments of each carbon and proton signals. This biogenetically interesting novel cyclic dipeptide was designated echinulin, being reported first in 1943 from the moulds of Aspergillus echinulatus; later on it was reported from the moulds of the A. glaucus group. Echinulin has since been isolated in this laboratory from three other plants, viz. two Orchidaceae plants, Dendrobium fimbriatum and Cymbidium aloifolium and the peels of an edible vegetable (fruits, Bengali name Potol) of Trichosanthes dioica (Cucurbitaceae). To our knowledge, this is the first report on the occurrence of this mould metabolite, echinulin in four higher plants belonging to three different families. The absolute configuration (S) at each of its two chiral centres and its mass fragmentation have also been discussed.

Recent advances in traditional plant drugs and orchids.

Abstract: The main objective of this paper is to review recent advances in plant drug research and developments in orchid study, in an attempt to provide useful references for plant drug studies. Plants have been used as medicine for millennia. Out of estimated 250 000 to 350 000 plant species identified so far, about 35 000 are used worldwide for medicinal purposes. It has been confirmed by WHO that herbal medicines serve the health needs of about 80 percent of the world's population; especially for millions of people in the vast rural areas of developing countries. Meanwhile, consumers in developed countries are becoming disillusioned with modern healthcare and are seeking alternatives. The recent resurgence of plant remedies results from several factors: 1) the effectiveness of plant medicines; 2) the side effect of most modern drugs; and 3) the development of science and technology. It has been estimated that in the mid-1990s over 200 companies and research organizations worldwide are screening plant and animal compounds for medicinal properties. Actually, several important drugs used in modern medicine have come from medicinal plant studies, eg, taxol/paclitaxel, vinblastine, vincristine, topotecan, irinotecan, etoposide, teniposide, etc. As for drugs derived from orchids, some novel discoveries, both in phytochemical and pharmacological properties, were reported by some universities. However, studies on plants are very limited. Only about a third of the million or so species of higher plants have been identified and named by scientists. Of those named, only a tiny fraction has been studied. Nowadays the linking of the indigenous knowledge of medicinal plants to modern research activities provides a new approach, which makes the rate of discovery of drugs much more effective than with random collection.

Chemistry, bioactivity and quality control of Dendrobium, a commonly used tonic herb in traditional Chinese medicine

Abstract: The fresh or dried stems of many Dendrobium species are well known as one of the most expensive tonics in traditional Chinese medicine Documented as a “superior grade” herbal medicine in the ancient text “Shen Nong’s Herbal Classic”, Dendrobium has been used for thousands of years and is now a popular health food worldwide The main chemical components of Dendrobium are alkaloids, aromatic compounds, sesquiterpenoids and polysaccharides, with multiple biological activities, including immunomodulatory, neuroprotective and anti-tumor effects, etc Various qualitative and quantitative methods have been developed for the quality evaluation of Dendrobium In this review, the research progress since the 1930s relating to the chemistry, bioactivity and quality control of Dendrobium is summarized, existing problems and prospects are also discussed

Structural Diversity and Biological Activities of Indole Diketopiperazine Alkaloids from Fungi

Abstract: Indole diketopiperazine alkaloids are secondary metabolites of microorganisms that are widely distributed in filamentous fungi, especially in the genera Aspergillus and Penicillium of the phylum Ascomycota or sac fungi. These alkaloids represent a group of natural products characterized by diversity in both chemical structures and biological activities. This review aims to summarize 166 indole diketopiperazine alkaloids from fungi published from 1944 to mid-2015. The emphasis is on diverse chemical structures within these alkaloids and their relevant biological activities. The aim is to assess which of these compounds merit further study for purposes of drug development.