Citrus aurantifolia(Christm.) Swingle (lime) Fruit Extract Inhibits the Activities of Polyol Pathway Enzymes

Abstract

Diabetes mellitus is associated with several complications, which may result from one or more factors including increased flux of polyol pathway. This study evaluated the inhibitory potential of four citrus fruits namely Citrus paradisi Macfad. (grape), Citrus limon (L.) Osbeck (lemon), Citrus aurantifolia (Christm.) Swingle (lime) and Citrus sinensis (L.) Osbeck (orange), on the activities of aldose reductase and sorbitol dehydrogenase -the two enzymes that mediate the polyol pathway. This is determined by incubating citrus extracts with appropriate enzymes and substrates. Fruit extract with the lowest half maximal inhibitory concentration (IC 50 ) was used to assess the mode of inhibition of the enzymes by preparing Lineweaver-Burk plot. Citrus fruits tested inhibited sorbitol dehydrogenase more than aldose reductase, which resulted in lowered IC 50 values. Of all the citrus fruits tested, lime fruit extract displayed potent inhibition of aldose reductase (IC 50 : 138.66 µg/mL) and sorbitol dehydrogenase (IC 50 : 47.21 µg/mL). Kinetic studies also revealed that lime fruit extract inhibited the activities of both enzymes in a competitive manner. In conclusion, the inhibition of the polyol pathway enzymes by the lime fruit extract may be attributed to the presence of phytochemicals such as flavonoids and limonoids.

Bioactive Components and Their Activities from Different Parts of Citrus aurantifolia (Christm.) Swingle for Food Development

“…This activity is associated with the presence of secondary metabolites found in the peel of C. aurantifolia. Kazeem et al (2020) [12] also showed that C. aurantifolia fruit could inhibit aldose reductase effectively with an IC 50 of 138.66 g/mL. Besides that, it can also inhibit sorbitol dehydroreductase with an IC 50 of 47.21 g/mL.…”

“…Kinetic studies also show that the extract can competitively inhibit the activity of both enzymes. Enzyme inhibition through the polyol pathway is associated with the presence of flavonoids and limonoids in the C. aurantifolia [12].…”

Phytochemical screening of ethanolic extract of local Aceh lime (Citrus aurantifolia (Christm.) Swingle) peels

“…Swingle is nutrient-rich and effective as a pesticide, anti-oxidant, anti-bacterial, anti-cancer, and anti-inflammatory agent [9]. These various biological activities are caused by the secondary metabolite content found in lime, namely coumarins, alkaloids, flavonoids [10], limonoids, carotenoids, phenolics, terpenes [11], and essential oils [12]. Every part of lime has benefits, including the peel, which is said to be a good source of pectin, essential oils, and phenolic compounds [13].…”

Phytochemical and Antioxidant Activity Evaluation of Lime (Citrus aurantifolia) Juice Powder

“…However, the juice of lime fruit also has metabolites that have antioxidant activity. Lime juice contains several natural antioxidant compounds, such as flavonoids (hesperidin, rutin, didymin) and limonoids (limonin), as well as ascorbic acid (Vitamin C) (Kazeem et al, 2020)). Lime juice contains ascorbic acid from 21.8 g/100g to 38.9 g/100g, and seedless lime has lime juice 60-66% that contains ascorbic acid of 118.2 -140.8 mg/100g (Shrestha et al, 2012).…”