We have one more Chemistry Doctorate in our community. Dr. Achyut Adhikari completed his PhD Degree form University of Karachi Pakistan in November 2009.
The title of his dissertation is “BIOPROSPECTING STUDIES ON SARCOCOCCA CORIACEA (HOOK. F.) OF NEPALESE ORIGIN”.
The summary of his dissertation is follows:
Although fluorine is the most abundant halogen in the Earth’s crust, fluorine containing natural products are extremely rare in nature. This is due to the special properties of fluorine such as: a) it is found in highly insoluble form, therefore it has less bioavailability, b) it has very high heat of hydration due to which it is a poor nucleophile in aqueous solution, and also c) redox potential which is required for the oxidation of fluoride is higher than that generated by the reduction of hydrogen peroxide, thus fluorine cannot be incorporated into organic compounds via the haloperoxidase reaction. Due to these reasons, the mechanism by which C-F bond formation can take place has attracted a considerable scientific interest. Only 18 organofluorine containing natural products have been reported so far. All of them are primary metabolites and no fluorine containing secondary metabolite has been reported from any natural source. This Ph. D. study has led to an exciting discovery of a novel class of fluoropyrimidine substituted alkaloids from a medicinal plant, Sarcococca coriacea of Nepalese origin.
Seven fluoropyrimidine containing steroidal alkaloids and one novel fluoropyrimidine substituted iononehave been obtained. This is the first time that fluorine containing secondary metabolites have been reported from any natural source, which has opened up a new avenue for further research in the chemistry of fluorine- containing secondary metabolites.
Additionally, nine known pregnane-type steroidal alkaloidshave also been isolated for the first time from S. coriacea, which include alkaloid-C, Na-ethylepipachysamine D, sarcovagenine C, sarcovagine D, N-methylpachysamine A , dictyophlebine, 5,6-dihydrosarconidine, terminaline, and iso-N-formylchonemorphine.
Congratulations to Dr. Adhikari on your great achievement and we all wish all the best for your bright future!!!!!!!!
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I found this periodic table very useful. This is regular periodic table with picture with each element. Picture is closely related to the element. This gives an impression of the element so that it is easy to know the element. For example: Sun and stars have plenty of hydrogen gas, Lithium is used in battery, Sodium is in our kitchen salt and so on. This periodic table also tells you whether the element is solid, liquid or gas by symbol, which is so cool.
In my high school we had remember the name and symbol of at least 20 elements with atomic number. Memorizing things without any clue is senseless, i guess. But we did it. This new periodic table will improve learning chemistry for beginners.
Periodic table gives info about chemical elements. Like everyone has to start reading and writing with alphabets of the language, periodic table is the alphabet of chemistry.
