Carbon-13 NMR spectroscopy of steroidal sapogenins and steroidal saponins

Haslam’s previous accounts of this area of flavonoid chemistry (Haslam, 1975, 1982a) eloquently summarized the historical developments in the chemistry and biochemistry of this important and complex group of plant phenolics. Also covered were their relationship with condensed tannins and aspects of their characteristic chemical and spectroscopic properties and metabolism.

Flavans and proanthocyanidins

The antioxidant activities of hot water extracts (HWECC) and ethanol extracts (EECC) from the dry bark of Cinnamomum cassia Presl were evaluated in this study. Results showed that at 1.0 mg/mL, the ethanol extracts of C. cassia (96.30%) exhibited a greater inhibition than the alpha-tocopherol (93.74%) on FeCl(2)-ascorbic acid induced lipid peroxidation of rat liver homogenate in vitro. From 0.05 to 1.0 mg/mL, the EECC demonstrated the highest superoxide anions scavenging activity and the strongest anti-superoxide formation activity (p < 0.05). The same extract also showed an excellent antioxidant activity in enzymatic and nonenzymatic liver tissue oxidative systems. EECC revealed the strongest antioxidant activity followed by alpha-tocopherol and HWECC. Compared to alpha-tocopherol, the IC(50) values of EECC were found to be lower in thiobarbituric acid test (IC(50) = 0.24 mg/mL vs 0.37 mg/mL), in cytochrome c test (IC(50) = 0.16 mg/mL vs 0.27 mg/mL) and in xanthine oxidase inhibition test (IC(50) = 0.09 mg/mL vs 0.19 mg/mL). The present study concludes that EECC could be used as a good source of antioxidant in the dietary supplement.

Antioxidant activity of Cinnamomum cassia

Aromatic glycosides from Berchemia racemosa

Protective effects of steroid saponins from Paris polyphylla var. yunnanensis on ethanol- or indomethacin-induced gastric mucosal lesions in rats: structural requirement for activity and mode of action.

Seven aromatic compounds from bark of Cinnamomum cassia

Previously, four steroid glycosides (Pa-d) were isolated from the rhizomes of Paris polyphylla SM. and characterized. In a continuation of our studies on this plant, a further five new steroid glycosides (1, 2, 12, 14 and 16) together with three known compounds (13, 18 and 19 ; the latter two have been obtained synthetically as acetyl derivatives) have been isolated and their structures established as follows. 1 and 2 : (22ξ, 25R)-22-methoxyfurostanol 3, 26-O-bisglycosides (proto-type saponins) corresponding to Pa [diosgein 3-O-α-L-ara·fur-(1→4)-[α-L-rha·pyr-(1→2)]-β-D-glc·pyranoside (3)] and Pb [diosgein 3-O-α-L-rha·pyr-(1→4)-α-L-rha·pyr-(1→4)-[α-L-rha·pyr-(1→2)]-β-D-glc·pyranoside (6)], respectively ; 12 and 13 : pennogenin oligosides having the same sugar moieties as 3 and 6, respectively ; 14 and 18 : pennogenin derivatives carrying 3-O-α-L-ara·fur-(1→4)-β-D-glc·pyranoside and hexaacetyl 3-O-α-L-rha·pyr-(1→2)-β-D-glc·pyranoside, respectively ; 16 and 19 : diosgenin derivatives carrying the same sugar moieties as 14 and 18, respectively.

Mitsuhiko Miyamura

Papers

Seven aromatic compounds from bark of Cinnamomum cassia

Steroid saponins from Paris polyphylla Sm.-supplement.