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Nolitha Nkobol

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Papers by Nolitha Nkobol

Research paper thumbnail of Towards Climate-Smart Agricultural Approach

URL: https://doi.org/10.15640/jaes.v5n2a5, Towards Climate-Smart Agricultural Approach: Prospect ... more URL: https://doi.org/10.15640/jaes.v5n2a5, Towards Climate-Smart Agricultural Approach: Prospect for Smallholder Farmers in Semi-Arid Regions

Research paper thumbnail of The state of innovation in South Africa: Findings from the South African National Innovation Survey

Research paper thumbnail of Three new α-glucosidase inhibitors from guggul, the oleogum resin of Commiphorawightii

Research paper thumbnail of Inhibitory activities α-glucosidase and α-amylase by Terminalia sericea Burch.Ex DC constituents

Diabetes mellitus is an endocrine disorder that affects more than 100 million people worldwide. S... more Diabetes mellitus is an endocrine disorder that affects more than 100 million people worldwide. South African plants namely Terminalia sericea, Euclea natalensis, Warbugia salutaris, Aloe ferox, Artemisia afra, Sclerocarya birrea, Spirostachys africana and Psidium guajava were investigated for their in vitro α-glucosidase and α-amylase properties, and antioxidant activities. Terminalia sericea stem bark extract showed the best results against α-glucosidase and α-amylase enzymes. Bioassay-guided fractionation of an acetone extract of T. sericea stem bark led to the isolation of four known compounds namely β-sitosterol (1), β-sitosterol-3-acetate (2), lupeol (3), and stigma-4-ene-3-one (4), in addition to two inseparable sets of mixtures of isomers [epicatechin-catechin (M1), and gallocatechin-epigallocatechin (M2). 1 and 3 showed the best inhibitory activity on α-glucosidase (IC 50 :54.5 and 66.5 µM). Bio-evaluation of the inhibitory activity of the purified compounds on α-amylase showed that 3 and 1 exhibited IC 50 values of 140.7 and 216.02 µM, respectively against α-amylase. Compounds 2, M1, 3 and M2 were found to be non-toxic to Vero cells. This study is the first to report -glucosidase and -amylase activity of M1, M2, 2 and 4 isolated from T. sericea, which validated the traditional use of the bark of T. sericea for diabetes in South Africa.

Research paper thumbnail of Towards Climate-Smart Agricultural Approach

URL: https://doi.org/10.15640/jaes.v5n2a5, Towards Climate-Smart Agricultural Approach: Prospect ... more URL: https://doi.org/10.15640/jaes.v5n2a5, Towards Climate-Smart Agricultural Approach: Prospect for Smallholder Farmers in Semi-Arid Regions

Research paper thumbnail of The state of innovation in South Africa: Findings from the South African National Innovation Survey

Research paper thumbnail of Three new α-glucosidase inhibitors from guggul, the oleogum resin of Commiphorawightii

Research paper thumbnail of Inhibitory activities α-glucosidase and α-amylase by Terminalia sericea Burch.Ex DC constituents

Diabetes mellitus is an endocrine disorder that affects more than 100 million people worldwide. S... more Diabetes mellitus is an endocrine disorder that affects more than 100 million people worldwide. South African plants namely Terminalia sericea, Euclea natalensis, Warbugia salutaris, Aloe ferox, Artemisia afra, Sclerocarya birrea, Spirostachys africana and Psidium guajava were investigated for their in vitro α-glucosidase and α-amylase properties, and antioxidant activities. Terminalia sericea stem bark extract showed the best results against α-glucosidase and α-amylase enzymes. Bioassay-guided fractionation of an acetone extract of T. sericea stem bark led to the isolation of four known compounds namely β-sitosterol (1), β-sitosterol-3-acetate (2), lupeol (3), and stigma-4-ene-3-one (4), in addition to two inseparable sets of mixtures of isomers [epicatechin-catechin (M1), and gallocatechin-epigallocatechin (M2). 1 and 3 showed the best inhibitory activity on α-glucosidase (IC 50 :54.5 and 66.5 µM). Bio-evaluation of the inhibitory activity of the purified compounds on α-amylase showed that 3 and 1 exhibited IC 50 values of 140.7 and 216.02 µM, respectively against α-amylase. Compounds 2, M1, 3 and M2 were found to be non-toxic to Vero cells. This study is the first to report -glucosidase and -amylase activity of M1, M2, 2 and 4 isolated from T. sericea, which validated the traditional use of the bark of T. sericea for diabetes in South Africa.

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