ABSTRACT
Lychee is a fruit of Asian origin with an exquisite flavor and an attractive reddish color. However, according to recent reports, the consumption of this fruit reduces the levels of blood glucose with adverse effects on human health such as encephalopathy and hypoglycemic. The objective of this work was to determine if the peel, pulp, and seed of "Brewster" lychee fruits harvested at two stages of maturity had antihyperglycemic effect. This effect was determined by an oral glucose tolerance test using Wistar rats. In addition, ultraviolet-visible spectrophotometry and high-resolution liquid chromatography were used to quantify phenolic compounds, flavonoids, organic acids (OAs), sugars, and antioxidant activity. Results indicated that stage I pulp (immature fruits) and stage II peel and seed (export mature fruits) reduced blood glucose levels, and the effects of the former two were synergistic with metformin. The pulp of mature fruits (stage II), however, lacked a hypoglycemic effect. Additionally, the peel and the seeds of these fruits presented a high antioxidant activity (as determined by DPPH [2,2-diphenyl-2-picryl-hydracyl] and ABTS+ [2,2-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid] methods), which correlated well with the total content of phenolic compounds. The highest content of polyphenolics, flavonoids, and OAs was found in the extracts of the peel and seeds of both stages of maturity. It was therefore concluded that "Brewster" mature lychees are safe for human consumption, and both the seed and the peel can be useful sources for obtaining new compounds with antihyperglycemic activity.
Subject(s)
Litchi , Animals , Antioxidants/pharmacology , Fruit , Hypoglycemic Agents , Plant Extracts/pharmacology , Rats , Rats, WistarABSTRACT
Lecanicillium (Verticillium) lecanii produced chitinases using shrimp shell as inducer. Maximum production of b-N-acetylglucosaminidase was measured at 80h. Enzyme stability was obtained at temperatures ranging from 30 to 40°C and maximum activity at 50°C, pH 6.0. Enzyme activity increased with Ba2+, Co2+, Fe3+ and Zn2+. Bioassays against the phytopathogenic fungus Oidium spp. showed mycelial and germination inhibition. SDS-PAGE electrophoresis of the partially purified extract revealed four bands of 70, 58, 45 and 31kDa and this extract showed activity of b-N-acetylglucosaminidase through zymogram analysis. Chitinases produced by L. lecanii are potentially useful against phytopathogenic fungi, insects and chitosan bioconversions.
Lecanicilium (Verticillium) lecanii produjo quitinasas mediante el uso de caparazón de camarón como inductor. La máxima producción de b-N-acetylglucosaminidasa se obtuvo a las 80h. Se observó estabilidad de la enzima en el intervalo de temperatura entre 30 y 40°C y su actividad máxima a los 50°C, pH 6,0. La actividad enzimática se incrementó con Ba2+, Co2+, Fe3+ and Zn2+. El bioensayo contra el hongo fitopatógeno Oidium spp. mostró inhibición micelar y de la germinación. La electroforesis SDS-PAGE del extracto parcialmente purificado mostró cuatro bandas de 70, 58, 45 y 31kDa y este extracto mostró actividad de b-N-acetylglucosaminidasa a través de un análisis de zimograma. Las quitinasas producidas por L. lecanii pueden ser potencialmente utilizadas contra hongos fitopatógenos, insectos y en la bioconversión del quitosán.
Lecanicillium (Verticillium) lecanii producido quitinases utilizou exoesqueleto do camarão como inductor. Produção máxima de b-N-acetilglucosaminidasa foi obtido em 80h. A estabilidade de enzima estava em o intervalo de temperaturas de 30 - 40°C e os niveis máximos de atividade enzimática foram obtidos em 50°C, pH 6,0. A atividade de enzima foi aumentada com Ba2+, Co2+, Fe3+ e Zn2+. O Bioensaios contra fungo fitopatógenos Oidium spp. mostrou inibição miceliar e germinação. O electroforesis SDS-PAGE do extrato parcialmente purificado revelou quatro faixas de 70, 58, 45 e 31kDa e este extrato apresentou atividade b-N-acetilglucosaminidasa através de uma análise zimograma. O quitinases produzido por L. lecanii são potencialmente capaz de ser utilizado contra fungos fitopatógenos, insetos e bioconversions de quitosano.