Photoprotective, antioxidant potential and DNA damage protection assay of leaf methanolic extract of Holoptelea integrifolia (Roxb) Planch and determination of some bioactive phenolic compounds by RP-HPLC

The methanolic leaf extract (MLE) of medicinally important plant Holoptelea integrifolia (Roxb.) Planch, a tree member of Ulmaceae family, exhibits prominent photoprotective and antioxidant activity mainly due to presence of phenols, flavonoids and tannins in notable amounts. Photopro-tective efficacy (Sun Protection Factor value) of MLE was found to be 16.265 & PLUSMN; 0.0077, which can effectively block around 93% UV-B radiation. The transmission erythema (%Te) and trans-mission pigmentation (%Tp) values are lowest (2.4102 & PLUSMN; 0.620 and 3.050984 & PLUSMN; 0.183 respec-tively) at highest concentration of MLE (500 & mu;g/ml). The antioxidant potential of MLE was evalu-ated by Reducing Power Assay (IC50 value: 88.52 & PLUSMN; 0.583 & mu;g/ml), DPPH (IC50 value: 61.96 & PLUSMN; 0.721 & mu;g/ml) and ABTS scavenging (IC50 value: 210.15 & PLUSMN; 0.329 & mu;g/ml) activities. Ul-traviolet (UV) ray induced DNA damage assay also revealed that MLE provide ample protection. Among the separated TLC fractions of MLE, four fractions (F2, F3, F4 & F7) were selected for fur-ther analysis. Six phenolic acids namely-tannic acid, gallic acid, hydroxybenzoic acid, p-coumaric acid, trans-cinnamic acid, caffeic acid and quercetin were identified from the RP-HPLC chro-matograms. Subsequent quantification of these identified phenolics revealed tannic acid as a dominant compound in F2 (45.06 & PLUSMN; 0.241 & mu;g/mg) and F7 (47.46 & PLUSMN; 0.189 & mu;g/mg), along with p-coumaric acid (104.12 & PLUSMN; 0.226 & mu;g/mg) and trans-cinnamic acid (108.19 & PLUSMN; 0.316 & mu;g/mg) in F3 and F4 respectively. So above findings indicate that MLE is endowed with rich source of medi-cinally potential phytometabolites with prominent UV-blocking and antioxidant property, which offer immense pharmaceutical prospects.

Automated summary

The methanolic leaf extract (MLE) of Holoptelea integrifolia has significant photoprotective and antioxidant activity due to a high concentration of phenols, flavonoids, and tannins. MLE was found to effectively block 93% of UV-B radiation, with the highest concentration providing the lowest transmission erythema and pigmentation values. The antioxidant potential of MLE was evaluated through various assays, and it was also shown to provide protection against UV-induced DNA damage. Phenolic acids, including tannic acid, gallic acid, and p-coumaric acid, were identified and quantified in different fractions of MLE. These findings suggest that MLE contains valuable phytocompounds with UV-blocking and antioxidant properties, offering promising pharmaceutical prospects.