Effects of Hibiscus sabdariffa Linn. fruit extracts on α-glucosidase enzyme,glucose diffusion and wound healing activities

Objective:To provide in vitro evidence for antidiabetic activity through potential inhibition of α-glucosidase enzyme,glucose diffusion and enhancement in the wound healing using methanolic extract and fractions from Hibiscus sabdariffa Linn.fruit.Methods:The inhibitory action of methanolic extract and fractions of such fruit on aglucosidase enzyme and glucose movement through in vitro assay assessment was reported.Their activities on wound healing were tested using the scratch assay.Results:Ethyl acetate fraction at 50 mg/m L concentration exhibited significant aglucosidase inhibition(95.79 mg/m L) with P < 0.05.At the same concentration,the methanolic extract as well as other fractions revealed lower α-glucosidase inhibition and higher glucose diffusion retardation across the dialysis tube than the control.Ethyl acetate and butanol fractions displayed notably higher glucose diffusion inhibitory activity of 5.21 mmol/L and 5.2 mmol/L,respectively as compared to methanolic extract and n-hexane fraction of 6.58 mmol/L and 6.49 mmol/L,respectively.Conversely,compared to other fractions the methanolic extract and ethyl acetate fraction manifested proliferative effect at the incubation time of 6 h during the wound healing study.Conclusions:It is established that methanolic extract and fractions from H.sabdariffa Linn.fruit can inhibit the α-glucosidase enzyme and glucose movement as well as influence the wound healing activity positively.

Tetracyclic triterpenoids isolated from semi-mangrove plant Hibiscus tiliaceus

A continuing phytochemical study on the semi-mangrove plant Hibiscus tiliaceus yielded two new tetracyclic triterpenoids （3β,24S）-19（10→9）-abeo-8α,9β,10α-eupha-5,25（26）-dien-3,24-diol （tiliacol A, 1 ）, and （3β,23Z）-19（10→9）-abeo-8α,9β,10α-tircalla-5,23-dien-3,25-diol （tiliacol B, 3）, together with one known analog （2）. Their structures were elucidated on the basis of extensive spectral analyses （MS, IR, 1D NMR and 2D NMR） and comparison with literature compounds. Compound 2 showed potent cytotoxicity against both P388 and HeLa cells with ICon values of 11.2 μmol/L and 11.5 μmol/L, resoectively.

黄槿化学成分的研究

目的研究黄槿Hibiscus tiliaceus枝叶的化学成分。方法采用硅胶柱色谱、Sephadex LH-20柱色谱分离化合物,并通过理化数据测定和波谱技术分析鉴定化合物的结构。结果从黄槿枝叶70%乙醇提取物中分离得到14个化合物,分别鉴定为木栓酮(1)、β-谷甾醇(2)、香草醛(3)、syriacusin A(4)、hibiscolactone(5)、莨菪亭(6)、臭矢菜素C(7)、反式丁烯二酸(8)、山柰酚(9)、槲皮素(10)、胡萝卜苷(11)、壬二酸(12)、丁二酸(13)、芦丁(14)。结论化合物7、9、10为首次从该属植物中分离得到,化合物3～5、8、12～14为首次从该植物中分离得到。

6种黄槿倍半萜类成分的衍生化改造和体外抗肿瘤活性研究

目的 对黄槿中6种天然倍半萜类成分进行衍生化改造,并对所得衍生物进行体外抗肿瘤活性评价,分析其构效关系。方法 选取各种芳胺对黄槿中发现的6种倍半萜成分进行席夫碱修饰,采用噻唑蓝(MTT)法考察合成的目标化合物对HeLa、HepG2和MCG-803细胞的体外抗增殖活性。结果 衍生改造了19个不同的倍半萜类衍生物,结合1H-NMR、13C-NMR、HR-MS确定其结构,其中17个衍生物首次得到。部分衍生物表现出良好的抗肿瘤活性,苄胺基团对此类骨架化合物的结构修饰能够较好地提高其抗肿瘤活性。结论 部分衍生物表现出良好的抗肿瘤活性,特别对HepG2细胞活性有较大的提高,化合物12、22、23具有进一步研究价值。