UPLC-QTOF-MS analysis of a carbonic anhydrase-inhibiting extract and fractions of Luffa acutangula (L.) Roxb (ridge gourd).
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BACKGROUND
Luffa acutangula (L.) Roxb, commonly known as ridge gourd (cucurbitaceae), is a common vegetable cultivated in India. It is also a well-used medicinal plant in Indian traditional medicine.
OBJECTIVE
To analyse the phenolics content of the most potent carbonic anhydrase-inhibiting fraction from an extract of L. acutangula.
METHODS
An aqueous ethanol extract of dried fruits of L. acutangula was successively fractionated into petroleum ether, dichloromethane and ethyl acetate. The extract and subsequent fractions were assessed for carbonic anhydrase-inhibitory activity and the enzyme inhibition kinetics were determined for the most active fraction. Total phenolic and flavonoid content of the extract and subsequent fractions were determined spectrophotometrically. Ultra-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry (UPLC-QTOF-MS) analysis was used to tentatively identify the major phenolics in the most active fraction.
RESULTS
The concentration of total phenolics and total flavonoids in the extract and each fraction thereof correlated with the level of carbonic anhydrase inhibition activity. The ethyl acetate fraction of the aqueous ethanol extract of L. acutangula had the highest carbonic anhydrase inhibition activity. The enzyme kinetics analysis indicated a mixed mode of inhibition. UPLC-QTOF-MS analysis of the ethyl acetate fraction indicated a number of phenolic acids, hydroxycoumarins, flavones, flavanones, and flavonoids.
CONCLUSIONS
The correlation of total phenolic content with carbonic anhydrase inhibition suggested further research that might confirm that phenolic compounds of L. acutangula offer potential therapeutic benefits against carbonic anhydrase-related disorders.
