Hunting for Potentially Bioactive Phytochemicals

Author

PROF DR EL SAYED ABOU TABL
Elsayed Ali Aboutabl
Professor of Pharmacognosy and Medicinal Plants, Faculty of Pharmacy, Cairo University,
Kasr-el-Aini Street, 11562 Cairo, EGYPT,
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Language

English

Title

Hunting for Potentially Bioactive Phytochemicals

Proceeding

7th INTRACOM – 2nd ICBWI 2009

Date

24th July 2009

Place Held

PWTC, Kuala Lumpur

Phytomedicine represents itself as a gift of nature, with a cosmic naturalness that makes it the obvious choice for a first treatment approach. Generations have made use of it, gained experience, and cherished it like a historical treasure, as a source of therapy. As early as 3000 B.C., the ancient Egyptians put much confidence in plants for curing many diseases. Hundreds of herbs are used in treating human diseases and are sold or traded in market places. Medicinal plants contain curative bioactive ingredients which proved to be valuable as primary or supplemental therapies when carefully applied. Despite the increasing use of synthetic drugs, phytoremedies have persisted as the ‘treatment of choice’ for different diseases in different countries throughout the world. However, many remedies have never been properly explored, researched, evaluated or exploited. The primary purpose of modern verification of traditional medicine is the assessment of therapeutic efficacy, as well as the establishment of qualitative and quantitative correlations between efficacy and chemical constituents. An effective approach proceeds through ethnopharmacological studies, action-guided isolation and identification of bioactive constituents and controlled clinical assessment of “Phytomedicines”. The lecture will shed light upon the results of recent studies dealing with bioactive phytochemicals from certain medicinal plants growing in Egypt, including M. quinquenervia and Crataegus sinaica Boiss. The major polyphenolic metabolites of M. quinquenervia were isolated, including the phenolic acid derivatives: gallic acid , ellagic acid , 3-O-methylellagic acid, 3,4,3'-tri-O-methylellagic acid , 2,3-O- exahydroxydiphenoyl-(α/β)-D-4C1-glucopyranose, as well as the ellagitannins:castalin and grandinin. Grandinin (the major compound) showed radical scavenging properties by its reaction with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical [EC50=4.3 ±0.3μg mL-1]. It was found to be relatively nontoxic in mice [LD50 = 316 mg Kg-1 b.wt.]. It exhibited a significant dose-dependent hypoglycemic effect by significantly reducing blood glucose level in basal condition and after heavy glucose load in normal mice. It reduced the elevated blood glucose level in STZ-induced diabetic mice.  In addition, grandinin reduced the elevated blood urea nitrogen and serum lipid peroxides in STZ-induced diabetic mice. The observed improvement in diabetic state and urea after administration of grandinin can be explained on the basis of its antioxidant properties. Extracts of the young stem, leaves and flowers of Crataegus sinaica Boiss growing in Egypt afforded quercetin, hyperoside, vitexin-2''-O-rhamnoside, epicatechin, procyanidin B2 and procyanidin C1.The cardiovascular and hepatoprotective activities of different fractions obtained from Crataegus sinaica leaves with flower, as well as the young stems were evaluated. Rats treated with the low and high dose of the extract of C. sinaica leaves with flowers showed 15% and 17% reduction in the heart rate, and reduction in the ST-segment by 107% and 57%, respectively. The T-amplitude was decreased by 59% of the high dose of the extract. Investigation of extracts from the young stems, as well as leaves with flowers on primary culture of rat hepatocytes monolayer indicated significant hepatoprotection for the total extract, ethyl acetate, butanol, and chloroform fractions at 100, 75, 75 and 25g/mL; respectively. The evaluated bioactivities were guaranteed safety by applying cytotoxicity test on hepatocytes monolayer. These bioactivities could be attributed to the main active constituents isolated.

Keywords

Bioactive Phytochemicals

Session

Symposium 4B (ICBWI)

Topic

Biomolecule Discovery