Li-Hua Su

The red resin of Dracaena cochinchinensis (Lour.) S.C. Chen, known as Chinese dragon’s blood, is formed through metabolic reprogramming following trunk injury, during which the original steroidal saponins are depleted and transformed. To investigate the steroidal degradation intermediates in this process, a systematic phytochemical study was conducted on the resin from Yunnan Province, leading to the isolation of 14 steroidal constituents (2 new and 12 known). The two new compounds, dracaenogenins C (1) and D (2), were identified as rare 12(13→14)-abeo-spirostanol aglycones, with 2 representing an unusual C-14α-hydroxylated derivative. Their structures, including absolute configurations, were unambiguously determined by comprehensive spectroscopic analysis (1D and 2D NMR, HRESIMS) and single-crystal X-ray diffraction. Biogenetic analysis suggests that these unusual aglycones arise from the acid-catalyzed Wagner–Meerwein rearrangement of diosgenin-type saponins via C-18 angular methyl migration (C-10→C-13) and C-ring contraction, serving as rare catabolic intermediates trapped during the metabolic shift from saponin accumulation to polyphenol biosynthesis. Furthermore, cytotoxicity evaluation against HepG2 cells revealed that while the parent glycosylated saponins (e.g., dioscin and gracillin) exhibited significant toxicity, the rearranged aglycones (1, 2, and 3) and other degradation products were devoid of cytotoxicity, supporting a detoxification mechanism during resin formation.

The fruits of Solanum torvum Swartz, a wild relative of eggplant, are consumed as a wild vegetable in tropical regions of Africa, Asia, and South America. In traditional Chinese medicine, it is believed to have anti-inflammatory and sedative effects. In the Philippines, water decoction is used to treat hyperactivity disorder. Twenty-two steroidal saponins were isolated and purified from the fruits grown in Yunnan, China, including six new compounds: torvosides U–Z (1–6). During drying and cooking, the saponins may undergo transformation, resulting in small amounts of sapogenins. These transformations can include dehydration of hydroxyl groups at position C22, formation of double bonds at position 20, 22 or 22, 23, and even formation of peroxide products. Saponin compounds torvoside X (4), torvoside Y (5), torvoside A (7), and (25S)-3-oxo-5α-spirostan-6α-yl-O-β-d-xylopyranoside (20), which are glycosylated at C-6, showed certain anti-epileptic activity in a pentylenetetrazole-induced zebrafish seizure model. No antiproliferative activity was detected when tested on the cancer cell line HepG2, and no hepatotoxic effect was noted on normal liver cell line LO2.

Panax notoginseng (Burk.) F. H. is a genuine medicinal material in Yunnan Province. As accessories, P. notoginseng leaves mainly contain protopanaxadiol saponins. The preliminary findings have indicated that P. notoginseng leaves contribute to its significant pharmacological effects and have been administrated to tranquilize and treat cancer and nerve injury. Saponins from P. notoginseng leaves were isolated and purified by different chromatographic methods, and the structures of 1–22 were elucidated mainly through comprehensive analyses of spectroscopic data. Moreover, the SH-SY5Y cells protection bioactivities of all isolated compounds were tested by establishing L-glutamate models for nerve cell injury. As a result, twenty-two saponins, including eight dammarane saponins, namely notoginsenosides SL₁-SL₈ (1–8), were identified as new compounds, together with fourteen known compounds, namely notoginsenoside NL-A₃ (9), ginsenoside Rc (10), gypenoside IX (11), gypenoside XVII (12), notoginsenoside Fc (13), quinquenoside L₃ (14), notoginsenoside NL-B₁ (15), notoginsenoside NL-C₂ (16), notoginsenoside NL-H₂ (17), notoginsenoside NL-H₁ (18), vina-ginsenoside R₁₃ (19), ginsenoside II (20), majoroside F₄ (21), and notoginsenoside LK₄ (22). Among them, notoginsenoside SL₁ (1), notoginsenoside SL₃ (3), notoginsenoside NL-A₃ (9), and ginsenoside Rc (10) showed slight protective effects against L-glutamate-induced nerve cell injury (30 µM).