Hyal-1 inhibitors from the leaves of Phyllanthus muellerianus (Kuntze) Excell

Abstract

Ethnopharmacological relevance: Leaves and twigs from Phyllanthus muellerianus Kuntze Excell are known to exert anti-inflammatory and antipyretic properties as well as wound healing properties. During a wide screening for human hyaluronidase-1 inhibitors from natural sources leaf extracts from P. muellerianus turned out to show basic anti-hyaluronidase activity. A detailed investigation of this effect should rationalize the potential anti-inflammatory activity of the extract for improved wound healing.

Aim of the study: The following study aimed to characterize the anti-Hyal-1 activity of the extract from P. muellerianus and to pinpoint the responsible natural products responsible for this bioactivity.

Materials and methods: Using cell surface displayed human Hyal-1 on Escherichia coli, the activity of inhibitors was determined by the stains-all assay method. A hydroalcoholic extract PWE from P. muellerianus was subjected to bioactivity-guided fractionation. Active compounds were characterized by means of mass spectrometry and NMR.

Results: PWE exerts a concentration dependent inhibition of Hyal-1 with an IC₅₀ of 80 μg/mL. Bioassay-guided fractionation revealed 13 compounds from the two most active fractions, mainly ellagitannins and flavonoid glycosides. The most activeHyal-1 inhibitor was found to be the ellagitannin chebulanin 10 (IC₅₀ 132 μM). This represents the first description of chebulanin in P. muellerianus.

Conclusions: The hydroalcoholic extract of P. muellerianus, as well as several subfractions obtained during bioassay-guided fractionation showed strong activity against Hyal-1. The main activity can be correlated to the ellagitanin chebulanin. Additionally, also synergistic effects are observed, indicating that the traditional use of aqueous extracts of P. muellerianus is justified, rather than the use of the isolated tannins. The traditional use of the plant as an anti-inflammatory agent for improved wound-healing can be rationalized by the anti-Hyal-1 activities of its constituents.

Keywords: Chebulanin; Ellagitannin; Hyaluronidase-1; Inflammation; Phyllanthus muellerianus; Wound-healing.