Pre-treatment of extracellular water soluble pigmented secondary metabolites of marine imperfect fungus protects HDF cells from UVB induced oxidative stress

Abstract

The present study explores the UVB-induced oxidative stress protective efficacy of the pigmented fungal metabolite (identified as DHICA: 5,6-dihydroxyindole-2-carboxylic acid - a melanin precursor) using human dermal fibroblast (HDF) cells. DHICA is a water soluble pigment of the marine Aspergillus nidulans strain SG 28. Preliminary compatibility studies revealed 95% HDF cell viability with 600 μM concentration of DHICA. HDF cells were exposed to UVB irradiation with and without DHICA pre-treatment and the morphological, physiological and molecular level changes were observed accordingly. The results suggested that UVB exposure increases reactive oxygen species (ROS) generation and subsequent DNA damage in HDF cells, whereas DHICA pre-treatment appreciably reduces ROS generation and DNA damage. DHICA pre-treatment upregulates the antioxidant enzyme expressions and reduces the number of cells in the sub-Go/G1 phase. Gene expression analysis of TNF-α, IL-6, COX-2, NF-κB, Bax and Caspase 3 suggested that pre-treatment with DHICA downregulates the above-mentioned genes and simultaneously upregulates Bcl2 expression. In vivo experiments with BALB/c mice suggested that the topical application of DHICA protected mice skin from UVB-induced oxidative stress (which increases the epidermal thickness as evidenced in the skin sectioning). Thus, DHICA application protects the cells from UVB induced oxidative stress and may find applications in sunscreen cosmetic preparations.

Asperyellone prevents HDF cells from UVB irradiation damages: An elaborated study

“…Hence, in all the experimental studies using HDF cells, the concentration of AY was fixed as 2 μM. The observations corroborate well with the recent reports of Shanuja et al on DHICA of fungal origin which protects HDF cells from UVB irradiation at concentrations ranging from 500 to 600 µM. Furthermore, reports of Lee et al on Cordycepin and Patwardhan and Bhatt on flavonoid enriched extract of clove as a UVB protecting agent for HDF respectively found similar to the observations made in the current study.…”

“…Hence, in all the experimental studies using HDF cells, the concentration of AY was fixed as 2 μM. The observations corroborate well with the recent reports of Shanuja et al 29 on DHICA of fungal origin which protects HDF cells from UVB irradiation at concentrations ranging from 500 to 600 µM. Furthermore, reports of Lee et al 30 In addition to ROS generation, UVB irradiations alter the mitochondrial membrane potential of the cells, which needs to be determined to authenticate the oxidative stress due to ROS generation.…”

“…Karthikeyan et al 5 reported that 7-Hydroxy coumarin pretreatment significantly reduced the peroxidation of membrane lipids and prevented the decrease in SOD, catalase, and GSH level at 30 µM concentration and restores the normal metabolism. Similarly, Shanuja et al 29 found attenuation of cellular antioxidant enzyme levels which is prevented by asperyellone (AY) pretreatment. In control group the cells remain intact and upon UVB exposure the integrity of DNA loses which is indicated by comet like structures.…”

“…Karthikeyan et al 5 reported that 7-Hydroxy coumarin pretreatment significantly reduced the peroxidation of membrane lipids and prevented the decrease in SOD, catalase, and GSH level at 30 µM concentration and restores the normal metabolism. Similarly, Shanuja et al 29 found attenuation of cellular antioxidant enzyme levels To further validate the UVB protective role of AY, studies were extended to assess the damages in cell DNA. In general, a break in DNA double strand is the most deleterious which leads to the loss of genetic material.…”

A Melanin-Related Phenolic Polymer with Potent Photoprotective and Antioxidant Activities for Dermo-Cosmetic Applications

“…The antioxidant properties of DHICA-melanin seem to also play a role in the maintenance of immune hyporesponsiveness to melanosomal proteins of relevance for the onset of autoimmune vitiligo [34]. Recently, a natural pigment isolated from marine Aspergillus nidulans and tentatively identified as a DHICA-melanin exhibited protective effects against Ultraviolet B (UVB)-induced oxidative stress in cellular and mice models [35,36]. UV radiations are known to be very harmful for the human skin, as they induce reactive oxygen species (ROS) production.…”