Evidence of late Palaeocene-early Eocene equatorial rain forest refugia in southern Western Ghats, India.

Equatorial rain forests that maintain a balance between speciation and extinction are hot-spots for studies of biodiversity. Western Ghats in southern India have gained attention due to high tropical biodiversity and endemism in their southern most area. We attempted to track the affinities of the pollen fl ora of the endemic plants of Western Ghat area within the fossil palynoflora of late Palaeocene-early Eocene (approximately 55-50 Ma) sedimentary deposits of western and northeastern Indian region. The study shows striking similarity of extant pollen with twenty eight most common fossil pollen taxa of the early Palaeogene. Widespread occurrences of coal and lignite deposits during early Palaeogene provide evidence of existence of well diversified rain forest community and swampy vegetation in the coastal low lying areas all along the western and northeastern margins of the Indian subcontinent. Prevalence of excessive humid climate during this period has been seen as a result of equatorial positioning of Indian subcontinent, superimposed by a long term global warming phase (PETM and EECO) during the early Palaeogene. The study presents clear evidence that highly diversifi ed equatorial rain forest vegetation once widespread in the Indian subcontinent during early Palaeogene times, are now restricted in a small area as a refugia in the southernmost part of the Western Ghat area. High precipitation and shorter periods of dry months seem to have provided suitable environment to sustain lineages of ancient tropical vegetation in this area of Western Ghats in spite of dramatic climatic changes subsequent to the post India-Asia collision and during the Quaternary and Recent times.

Chemistry and uses of pectin--a review.

Pectin is an important polysaccharide with applications in foods, pharmaceuticals, and a number of other industries. Its importance in the food sector lies in its ability to form gel in the presence of Ca2+ ions or a solute at low pH. Although the exact mechanism of gel formation is not clear, significant progress has been made in this direction. Depending on the pectin, coordinate bonding with Ca2+ ions or hydrogen bonding and hydrophobic interactions are involved in gel formation. In low-methoxyl pectin, gelation results from ionic linkage via calcium bridges between two carboxyl groups belonging to two different chains in close contact with each other. In high-methoxyl pectin, the cross-linking of pectin molecules involves a combination of hydrogen bonds and hydrophobic interactions between the molecules. A number of factors--pH, presence of other solutes, molecular size, degree of methoxylation, number and arrangement of side chains, and charge density on the molecule--influence the gelation of pectin. In the food industry, pectin is used in jams, jellies, frozen foods, and more recently in low-calorie foods as a fat and/or sugar replacer. In the pharmaceutical industry, it is used to reduce blood cholesterol levels and gastrointestinal disorders. Other applications of pectin include use in edible films, paper substitute, foams and plasticizers, etc. In addition to pectolytic degradation, pectins are susceptible to heat degradation during processing, and the degradation is influenced by the nature of the ions and salts present in the system. Although present in the cell walls of most plants apple pomace and orange peel are the two major sources of commercial pectin due to the poor gelling behavior of pectin from other sources. This paper briefly describes the structure, chemistry of gelation, interactions, and industrial applications soft pectin.

The Ayurvedic medicines Haritaki, Amala and Bahira reduce cholesterol-induced atherosclerosis in rabbits.

Four groups of 25 rabbits each, were studied to determine the effect of Haritaki (Terminalia chebula), Amla (Emblica officinalis) and Bahira (Terminalia belerica) on cholesterol-induced hypercholesteolaemia and atherosclerosis. The control group was fed with cholesterol alone; the Haritaki group received Haritaki and cholesterol; the Bahira group received Bahira and cholesterol; and the Amla group received Amla and cholesterol for 16 weeks. Cholesterolaemia was significantly less (P less than 0.001) in the Haritaki group (166 mg/dl), the Bahira group (240 mg/dl) and the Amla group (205 mg/dl) than in the control group (630 mg/dl). The Haritaki group had significantly less cholesterolaemia (P less than 0.001) as compared to the Bahira and Amla groups. Aortic sudanophilia was significantly less (P less than 0.001) in the Haritaki group (6%), the Bahira group (16%), and the Amla group (12%) than in the control group (38%). The cholesterol contents of the liver and aorta, respectively, were significantly less in the Haritaki group (46 mg/100 g, 28 mg/100 g), the Bahira group (78 mg/100 g, 72 mg/100 g) and the Amla group (46 mg/100 g, 42 mg/100 g), than in the control group (604 mg/100 g, 116 mg/100 g). Among the drug-fed groups, the Haritaki group had significantly lower degrees of sudanophilia and cholesterol content of aorta and liver (P less than 0.001) as compared to the Bahira and Amla groups. Although all three drugs reduced serum cholesterol, aortic sudanophilia and cholesterol contents of liver and aorta, their effects were in ascending order of magnitude. The drugs did not influence serum triglyceride levels, euglobulin clot lysis time or platelet adhesiveness.(ABSTRACT TRUNCATED AT 250 WORDS)