THESIS
1995
xiv, 182, [26] leaves : ill. ; 30 cm
Abstract
The dried fruit of Schisandra chinensis (Turcz.) Baill. (Magnoliaceae) is commonly used in Chinese medicine as a tonic and sedative. The major active ingredients are lignans of the dibenzo[a,c]cyclooctadiene type, many of which show liver-protective and antioxidant effects. During the course of reinvestigating the chemical composition and antioxidant property of this crude drug, sixteen lignans, two sesquiterpenes and one 1,3-disubstituted glycerol together with a ubiquitous phytosterol were isolated from the petroleum ether extract (see Fig.). Identification of these compounds was accomplished by a combination of spectroscopic methods (UV, IR,
1H-NMR,
13C-NMR and MS). The identities of some of the compounds were also confirmed by co-TLC with authentic samples....[
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The dried fruit of Schisandra chinensis (Turcz.) Baill. (Magnoliaceae) is commonly used in Chinese medicine as a tonic and sedative. The major active ingredients are lignans of the dibenzo[a,c]cyclooctadiene type, many of which show liver-protective and antioxidant effects. During the course of reinvestigating the chemical composition and antioxidant property of this crude drug, sixteen lignans, two sesquiterpenes and one 1,3-disubstituted glycerol together with a ubiquitous phytosterol were isolated from the petroleum ether extract (see Fig.). Identification of these compounds was accomplished by a combination of spectroscopic methods (UV, IR,
1H-NMR,
13C-NMR and MS). The identities of some of the compounds were also confirmed by co-TLC with authentic samples.
The biphenyl system of Schisandra lignans can exist in two configurations, the R-form and the S-form, distinguishable by circular dichroism. The NMR chemical shifts of the isolated lignans of the dibenzo[a,c]cyclooctadiene type were analyzed in detail with the aid of COLOC, HMBC and NOESY experiments, allowing the assignment of quaternary carbons. A general trend was observed in the carbon chemical shifts in connection with the substitution patterns. However, no significant trend was observed due to the biphenyl configurations.
Despite the similarity in the structures of the dibenzo[a,c]cyclooctadiene lignans, an HPLC method was established to separate fifteen isolated compounds within a reasonable time interval. The method can be adopted for plant drug analysis.
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