| Rubus suavissimus S.Lee is a perennial frutex deciduous which widely distributed in Kwangshi China, so it was also called Kwangshi Sweet tea. It has been used as tea drinks and sweetening agents in the folk for a long time. It was also used as traditional medicine for eliminating phlegm by cooling, expelling phlegm to arrest coughing and homeostatic elimination of stagnation.In order to built a foundation for the further exploitation of Rubus suavissimus S Lee, a series pharmacological tests and systematic analyses on the chemical structure of the extraction from the leaves of sweet tea have been carried on, and the results were followed:(1) The active compounds were extracted from the leaves, and the medicinal functions were studied. Four crude fractions (combin ed by thin-layer chromatography test) were separated by the Amberlite column according to the change of the ethanol concentration (from100%to10%, v/v), which marked Fraction Ⅰ～Fraction Ⅳ. According to the result, The Fraction Ⅱ and FractionⅣshows the inhibition on S-mutans, and the Fraction Ⅰ shows the anti-oxidant activities, while the FractionⅢ and FractionⅣ has the strongest insulin-stimulating activities.(2) The further studies on the analyses of chemical structures were carried out, and twenty-four compounds were purified and eluted from these fractions by using the1D and2D-NMR, IR, UPLC-MS and HPLC methods. There were eleven diterpenoid compounds as followed: Steviol; Ent-16β,17-dihydroxy-Kaurane-3-one; Ent-16β,17-dihydroxy-Kaurane-19-oic acid;16α,17,19-trihydroxy-ent-kaurane;3β,16a,17-trihydroxy-ent-kaurane,7β-hydroxyl-steviol; Rubusoside; Rubusoside-A;11,15-dihydroxy-ent-kaurane-16-en-18-oic-acid;16α-17-dihydroxy-ent-kaurane-19-oic-acid;13,17-dihydroxy-ent-kaurane-15-en-19-oic-acid; Ent-kaurane-3α,16β,17-triol-17-O-β-D-glucoside; Five triterpene compounds as followed:2α,3β-dihydroxy-ursane-12-en-28-oic-acid;2α,3β,23-trihydroxy-ursane-12-en-28-oic-acid;2α,3β,19α,23-tetrahydroxy-ursane-12-en-28-oic-acid;2α,3β,19α,23,24-pentacarbonyl-ursane-12-en-28-oic-acid. Four Flavonoid compounds as followed: Quercetin; Quercetin-3-O-β-D-glucopyranoside; Quercetin-3-O-α-D-ribopyra-noside; Kaempferol-3-O-β-D-6-O-trans-P-coumaryol-glucopyranoside; and four other compounds as followed:7,8-dihydro-buddlenol-B (erythro);7,8-dihydro-buddlenol-B (threo);7S,8R-dihydrodyhydroconiferyl alcohol and Sucrose.(3) According to the test, the rubusoside has strong anti-bacteria activity, and the200μg/mL rubusoside exhibited more than99%inhibition against the growth of Streptococcus mutants. In order to explore the mechanism of antibacterial action, series of tests were conducted and the results showed that:the rubusoside has strong anti-effect against the acidogenicity of Streptococcus mutants, cell surface hydrophobicity, adhesive force, the enzyme activity of GTF, and the synthesis of WIG(4) Recent researches showed that the rubusoside was valuable in the treatment of diabetes. The mice were rendered diabetic by a single intra peritoneal injection of alloxan, after confirmation of TIDM, control and diabetic mice were further separated into six groups:control, low dose (C), highdose(C), diabetic, low dose (D), high dose (D).At the end of the experiment, the determinations of serum glucose concentration were carried out, and the Hypoglycemic mechanism was explored. The results showed that the rubusoside could increase the secretion of insulin, and could obviously decrease the serum glucose concentration. The hypoglycemic rates were more than20%(200and300mg/kg.d), while the highest rate reaches27%(300mg/kg.d)(5) At the end, Toxicology tests were carried out in order to study the toxicity and safety of rubusoside. The result showed the LD50of rubusoside were3.709g/kg (Mice)4.735g/kg (Rats) which belongs to the low-toxicity level. After the acute and chronic toxicity experiments, the weights, dynamiting, hematology and blood biochemistry were belongs to the normal range, no obviously representational changes in major organs, which means the rubusoside has no obvious toxicity on the growth and development, blood system or hepatorenal functions. |
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