ABSTRACT
OBJECTIVE： To compare inhibitory effects of ethanol extract of different medicinal parts （root， stem， leaf， seed， flower and flesh） from Syzygium jambos on the activities of α-glycosidase and α-amylase. METHODS： Using half-inhibitory concentration value （IC50） as evaluation index， acarbose as positive control， inhibitory effects of ethanol extract of different medicinal parts from S. jambos on the activities of α-glycosidase （from yeast and small instestine in mice） and α-amylase were evaluated with in vitro inhibition model. The enzymatic dynamics and Lineweaver-Burk methods were used to analyze the inhibitory type of the best medicinal part on the activities of α-glycosidase and α-amylase. RESULTS： In the yeast α-glucosidase inhibitory activity test， the order of inhibitory activity was S. jambos seed＞S. jambos stem＞S. jambos leaf＞S. jambos root＞S. jambos flower＞S. jambos flesh＞acarbose. In the mice intestine α-glucosidase inhibitory activity test， the order of inhibitory activity was S. jambos seed＞S. jambos stem＞S. jambos root＞S. jambos leaf＞S. jambos flower＞S. jambos flesh＞acarbose. In the α-amylase inhibitory activity test， the order of inhibitory activity was acarbose＞S. jambos seed＞S. jambos stem＞S. jambos root＞S. jambos leaf＞S. jambos flesh＞S. jambos flower. Ethanol extract of S. jambos seed had the stronger inhibition activity against α-glucosidase from yeast，α-glucosidase from small intestine in mice and α-amylase than other medicinal parts [IC50 were（6.64±0.24）， （32.77±2.46） and （41.18±1.63） μg/mL]. Ethanol extract of S. jambos seed had the stronger inhibition activity against α-glucosidase than acarbose [IC50 to α-glucosidase from yeast and α-glucosidase from small intestine in mice were （2 833.33±5.48）， （1 304.21±6.45） μg/mL] （P＜0.05）. The inhibitory effect of ethanol extract from S. jambos on the activity of α-amylase was less than that of acarbose [IC50 was （27.27±1.24） μg/mL] （P＜0.05）. Enzymatic dynamics showed that the inhibitory type of ethanol extract from S. jambos seed on α-glucosidase and α-amylase were both reversible competitive inhibition. CONCLUSIONS： Among different parts of S. jambos such as root， stem， leaf， seed， flower and flesh， S. jambos seed shows the strongest inhibitory effects on the activities of α-glucosidase and α-amylase， which has the value of being developed for the treatment of diabetes or health food.
ABSTRACT
Objective: To study the chemical constituents from the stems of Syzygium jambos var. jambos. Methods: The phyotchemicals were isolated by using various chromatographic techniques such as silica gel, Sephadex LH-20, alumina column chromatography, and preparative HPLC process. The structures were elucidated on the basis of spectral data analysis. Their cytotoxicity against human liver cancer cells Huh-7 was conducted using MTT assay. Results: Twelve compounds were isolated from the EtOAc and MeOH extracts in the stems of S. jambos and identified as alphitolic acid (1), urolithin A (2), dibutyl phthalate (3), betulinic acid (4), ursolic acid (5), 1-(4-methoxyphenyl)-1, 2-propanediol (6), 2, 6-dimethoxy-1, 4-benzoquinone (7), diisobutyl phthalate (8), β-sitosterol (9), 3-acetyl-ursolic acid (10), asiatic acid (11), and arjunolic acid (12), respectively. All tested compounds 1, 7, 10, and 11 + 12 mixture did not show the cytotoxic activities towards human tumor cells Huh-7 in the test range up to 50 μmol/L. Conclusion: Except compound 4, the other 11 compounds are obtained from this plant for the first time. All tested compounds exhibit no significant cytotoxic activity against Huh-7 cells.
ABSTRACT
Syzygium jambos (L.) Alston, Myrtaceae, é empregado na medicina popular como digestivo e antiinflamatório. A triagem fitoquímica da droga pulverizada (folhas) indicou a presença de flavonóides, taninos e óleo volátil. O extrato hidroetanólico a 70 por cento das folhas de S. jambos foi preparado por percolação e liofilizado. O conteúdo de taninos das folhas e do extrato foi calculado, respectivamente, em 21,9 por cento e 43,3 por cento. O teor de flavonóides foi de 0,6 por cento (folhas) e 1,2 por cento (extrato). A administração oral prévia do extrato (400 mg/kg) a ratos Wistar reduziu significativamente as lesões gástricas induzidas por etanol acidificado. No modelo de úlcera subcrônica, com indução de lesão gástrica utilizando ácido acético a 30 por cento, o tratamento com o extrato (400 mg/kg) não apresentou resultado significativo. A atividade antioxidante do extrato foi avaliada através dos modelos de lipoperoxidação e de medida de capacidade seqüestrante de radicais DPPH. Os valores obtidos de Q1/2 (MDA) e CE50 (DPPH) foram, respectivamente, 0,17 μg/mL e 5,68 μg/mL.
Syzygium jambos (L.) Alston, Myrtaceae, is commonly employed in folk medicine as digestive and anti-inflammatory. Phytochemical screening of the powdered dried leaves indicates the presence of flavonoids, tannins and essential oil. Hydroethanol extracts (70 percent) were prepared by percolation and freeze-drying. The tannin content of dried leaves and extract was, respectively, 21.9 percent and 43.3 percent. The flavonoid content was 0.6 percent (dried leaves) and 1.2 percent (extract). Previous oral administration of S. jambos leaves extract (400 mg/kg) to rats reduced significantly gastric injury induced by HCl/ethanol. At the subcronic ulcer model by induction with 30 percent acetic acid the results were not significant. In vitro antioxidant activity of S. jambos extract was evaluated by malondialdehyde (MDA) and DPPH free radical method. The Q1/2 for MDA assay was 0.17 μg/mL and the EC50 for DPPH assay was 5.68 μg/mL.