Hunsa Prawat

Cyanogenic and non-cyanogenic glycosides from Manihot esculenta

In addition to lotaustralin and linamarin, a novel cyanogenic glycoside, 2-((6-O-(beta-D-apiofuranosyl)-beta-D-glucopyranosyl)oxy)-2-met hylbutanenitrile , two novel non-cyanogenic glycosides, (2S)-((6-O-(beta-D-apiofuranosyl)-beta-D- glucopyranosyl)oxy)butane and 2-((6-O-(beta-D-apiofuranosyl)-beta-D-glucopyranosyl)oxy)propane, and a simple non-cyanogenic glycoside, ethyl beta-D-glucopyranoside, were isolated from an ethanolic extract of the fresh root cortex of Manihot esculenta. From a methanolic extract of the fresh leaves of this species lotaustralin and linamarin, and two flavonoid glycosides, kaempferol-3-O-rutinoside and quercetin-3-O-rutinoside were isolated.

Prenylated flavanones from Derris reticulata

Abstract Two new pyranoflavanones, 2‴,3‴-epoxylupinifolin and dereticulatin, together with the known flavonoid lupinifolin, were identified from the stems of Derris reticulata . The structures and NMR spectral data were assigned by the use of 2D NMR technology and chemical transformations. All of the isolates showed cytotoxic activity in the P-388 cell line.

Bioactive scalaranes from the Thai sponge Hyrtios gumminae.

Chemical investigation of the Thai sponge Hyrtios gumminae collected from Similan Island in the Andaman Sea, Thailand, yielded four new sesterterpenoids, similan A (1), 12beta,20-dihydroxy-16beta-acetoxy-17-scalaren-19,20-olide (2), 12beta-acetoxy-20-hydroxy-17-scalaren-19,20-olide (3), and 12beta,16alpha,20-trihydroxy-17-scalaren-19,20-olide (4), together with seven known compounds. The structures of these new compounds were elucidated on the basis of their spectroscopic data and chemical transformations. Some of the isolated compounds were tested for their cytotoxic activity.

Investigation of some bioactive Thai medicinal plants

It has been estimated that plants are the most important source of medicine for more than 80% of the world’s population. Medicinal plants are a vital source of medication in developing countries. Despite the wealth of human experience and folklore concerning the medicinal uses of plants, proper scientific investigation has only been applied to a small fraction of the world’s plants. This is a cause of grave concern as plant species continue to disappear. A rapid response to this situation is urgently needed to prevent the disappearance of the plant species and the ethnopharmacological knowledge that accompanies them. In this review, recent work on the investigation of selected bioactive Thai medicinal plants is presented. Their biological activities against infectious diseases including antimalarial and anti-HIV, are highlighted, as well as their anticancer, antiulcer and anti-inflammatory properties. The chemical transformations of some selected compounds are discussed.

Anti-metastatic effects of aqueous extract of Helixanthera parasitica

Metastasis, the spread of cancer in body, is a major cause of death. We have screened anti-metastatic activity of aqueous and dichloromethane extracts of several not previously studied Thai herbs, using an in vitro invasion test. This involves the in vitro invasion of HCC-S102, a hepatocellular carcinoma cell line derived from a Thai patient, through a reconstituted-basement membrane (Matrigel). The aqueous extract of a plant (Helixanthera parasitica) revealed a significant inhibitory effect on the cancer cell invasion, and showed antioxidant activity. The aqueous extract was partially purified by silica gel column chromatography, and the highest anti-metastatic activity fraction showed 83% inhibition of invasion with low cytotoxic effect. However, anti-metastatic activity was not associated with the antioxidant activity of the aqueous extract.

Chemical Investigation Of Mammea Siamensis

A new 4-alkylcoumarin, mammea B/AC cyclo D ( 1 ), together with a 4-phenylcoumarin, mammea A/AC cyclo D ( 2 ), were isolated from the hexane extract of the dried flower of Mammea siamensis . Their structures were determined on the basis of spectroscopic evidence.

Lupane, friedelane, oleanane, and ursane triterpenes from the stem of Siphonodon celastrineus Griff.

Twenty-one triterpenes consisting of a lupane derivative, two friedelanes, an oleanane derivative, and 17 ursane-type triterpenoids, together with three known triterpenes, three sterols, a fatty acid, a sesquiterpene alkaloid, and a glycerol derivative, were isolated from the stem of Siphonodon celastrineus. Their structures were characterized by various spectroscopic techniques, as well as comparison with literature data. Twenty-seven metabolites of these were evaluated for cytotoxic activity against six human cancer cell lines. The biosynthetic formation of a 1,4-dioxane bridge is also discussed.

Terpenoids from the roots of Drypetes hoaensis and their cytotoxic activities.

Seven terpenoids consisting of five sesquiterpenoids, hoaensieremone, hoaensieremodione, hoaensifuranonal, hoaensieudesone, and hoaensibenzofuranal, and two friedelane triterpenoids, 3α-(E)-p-coumaroyloxyfriedelan-7-one and 3α-(E)-caffeoyloxyfriedelan-7-one were isolated from the dichloromethane extract of the roots of Drypetes hoaensis. Additionally, twelve known compounds and vanillin were isolated. Their structures were established on the basis of spectroscopic analysis, as well as by comparison with literature data. The anticancer activity of nine of these compounds was investigated.

Cytotoxic natural products from thai plants: a recent study.

Natural products will continue to be the most prolific source of bioactive compounds. Natural products exhibiting antitumor activity continue to be the subject of extensive research aimed at the development of drugs for the treatment of different human tumors. It is generally accepted that natural products offer a diversity and complexity of structure unmatched by even the most active imaginations of synthetic organic chemists. This paper reviews the research of selected Thai plants for the discovery of therapeutic agents. Attention will be focused on our recent research on Thai plants that possess cytotoxic properties. Synthetic modification and reaction of some of these compounds aimed at enhancing their potency will also be presented.

Ailanthusins A-G and nor-lupane triterpenoids from Ailanthus triphysa

Bioactivity-guided chemical investigation of the CH2Cl2 and CH2Cl2MeOH extracts of the stem and stem bark material of Ailanthus tryphysa (Simaroubaceae) led to the isolation of five cycloapotirucallanes, ailanthusins A-E, two malabaricanes, ailanthusins F-G, and one nor-lupane triterpenoid, 29-nor-lup-1-ene-3,20-dione along with twenty known compounds. Their structures were elucidated through the application of extensive spectroscopic methods, and the structure of ailanthusin A was further confirmed by single crystal X-ray analysis. Several malabaricane derivatives were prepared from malabaricol and, together with some of the isolates, were evaluated for their cytotoxic activities against human cancer and normal cell lines.