Antibacterial and α-glucosidase inhibitory activity in vitro of Bassia longifolia, a traditional medicinal plant from Nepal

Bassia longifolia KOENIG (=Madhuca longifolia KOENIG, Sapotaceae) is an evergreen tree which grows about 20 m in height and is one of more than 1600 different plant species that are used for traditional phytomedicine in Nepal. The bark is used internally, as a decoction for diabetic patients. Externally, the bark paste can be applied on cuts and wounds to stop bleeding.

Phytochemical investigations for the bark revealed the occurrence of different flavan-3-ols including some with rare epiafzelechin-units. Regarding pharmacological studies, only a few for wound healing properties and none for the use in diabetes are reported. Therefore, fractions of the bark were tested for their antibacterial activity as a possible assisting effect in wound healing. Furthermore, an α-glucosidase assay was performed with the same fractions and with 15 flavan-3-ols isolated from the bark. As a result, only fractions enriched with oligomeric proanthocyanidins (PA) and polymeric PAs showed antibacterial activity. The effect increased with a higher concentration of polymeric PAs. Moreover, all tested substances and fractions showed high α-glucosidase inhibition. Again, fractions with a high content of polymeric PAs showed a stronger effect. The substances showed an increasing inhibition with a rising degree of polymerisation. The intramolecular linkage also affected the outcome. A 4α-configuration and 4→6 linkage caused a higher inhibition than 4β→8 configurated flavan-3-ols. In conclusion, for the traditional use of the bark of B. longifolia, the first evidence as an antidiabetic drug is given in this study ([Fig. 1]).

Fig. 1 In vitro inhibition of α-glucosidase by oligomeric and polymeric proanthocyanidins from the bark of Bassia longifolia

 

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Artikel online veröffentlicht:
16. November 2023