Molecular profiling of marine endophytic fungi from green algae: Assessment of antibacterial and anticancer activities

Highlights

• Endophytic fungi Penicillium oxalicum isolated from marine algae Chaetomorpho anteria.

• Bioactive metabolites content in the ethyl acetate extract of P. oxalicum was analyzed by GC–MS.

• Bioactive metabolites were checked cytotoxicity and antibacterial assay.

Abstract

Bioactive natural metabolites, especially from the marine endophytic fungi, are largely unexplored. Endophytic fungi are being increasingly recognized as a group of organisms that produce novel metabolites of industrial importance. This study investigated the anticancer and antibacterial potential of the marine algal endophyte, Penicillium chrysogenum. The different organic solvent extracts of the endophytic fungi grown on different growth medium were analyzed for anticancer and antibacterial activities. The highest inhibitory activity was observed for the ethyl acetate (EA) extract of the culture filtrate grown in potato dextrose broth (PDB) for 21 days, against the tested human breast cancer cell (MCF-7) line. Similarly, the PDB-EA extract showed an appreciable activity against the human pathogens. The biochemical analysis of the Cha EA metabolites revealed terpenoids, steroids, phenolics and flavones. Gas Chromatography (GCMS) data revealed several bioactive compounds such as anthraquinone and cinnamic acid. The Cha EA extract induced membrane damage and thus, apoptosis in MCF-7cells. The secondary metabolites produced by these marine endophytic fungi have contributed to considerable anticancer and antimicrobial activities and hence, this study is an evidence of potential sources of antimicrobial and anticancer compounds from Penicillium chrysogenum.

Introduction

The quest for new potent drugs has always persisted crucial throughout human history. Most of the naturally derived metabolites are by products of microorganisms [1]. Around 10% of the world's biodiversity has been investigated for potential bioactivities, however, still, there are many more lead natural metabolites awaiting discovery [2]. The discovery of marine associated metabolites initially exploited macro organisms such as sponges, corals, and algae. However, now the focus has been shifted onto marine microorganisms such as fungi and bacteria [3]. Natural products and naturally derived compounds are generated by marine microorganisms, which have been used for treating human diseases [4]. Natural products derived from marine algae have been the basis of the treatment of several human diseases and thus, natural products are still considered to be valuable sources of drug leads [5].

The marine diversity is well known for incomparable groups of macro and microorganisms generating a wide range of secondary metabolites. Endophytes usually have a mutual relationship with their hosts [6] and most of them produce novel secondary metabolites of industrial potential [7]. Endophytic fungi are chemical synthesizers [8] and ubiquitous organisms, which are found associated with marine algae, residing intercellular or intracellular. The diversity in the marine environment influences the researchers to explore marine microflora with an array of beneficial aspects; the interactions between the marine microbial diversity and algae have opened new avenues in the synthesis of new metabolites.

Endophytic fungi reside in the marine algal living tissues and are potential sources of novel natural products for exploitation in medicine, agriculture, and industry [[9], [10], [11]]. There are only few studies on the marine algal endophytes as a source of natural products of pharmaceutical and agricultural importance [12]. Therefore, the bioprospecting endophytes offer a tremendous promise in the discovery of associated marine algal secondary metabolites, and novel lead compounds with therapeutic potential. Valuable products from microbial sources are usually easier and more economical to produce.

There are several reports on the anticancer and antimicrobial activities of the endophytic isolates from various marine algae [13,14]. However, the endophytes of Chaetomorpha antennina, and their anticancer and antimicrobial values have not yet been investigated. In this course of investigation, the endophytic fungi from the marine algae C. antennina, collected from Kovalam and Chennai, India were isolated and screened for bioactive metabolites. Further, the bioactive compounds were identified using hyphenated techniques.