Effectiveness of Phytoactive Molecules on Transcriptional Expression, Biofilm Matrix, and Cell Wall Components of Candida glabrata and Its Clinical Isolates

Abstract

Toxicity challenges by antifungal arsenals and emergence of multidrug resistance scenario has posed a serious threat to global community. To cope up with this alarming situation, phytoactive molecules are richest, safest, and most effective source of broad spectrum antimicrobial compounds. In the present investigation, six phytoactive molecules [cinnamaldehyde (CIN), epigallocatechin, vanillin, eugenol (EUG), furanone, and epigallocatechin gallate] were studied against Candida glabrata and its clinical isolates. Among these, CIN and EUG which are active components of cinnamon and clove essential oils, respectively, exhibited maximum inhibition against planktonic growth of C. glabrata at a concentration of 64 and 128 μg mL –1 , respectively. These two molecules effectively inhibited and eradicated approximately 80% biofilm of C. glabrata and its clinical isolates from biomaterials. CIN and EUG increased reactive oxygen species generation, cell lysis, and ergosterol content in plasma membrane and reduced virulence attributes (phospholipase and proteinase) as well as catalase activity of C. glabrata cells. Reduction of mitochondrial membrane potential with increased release of cytochrome c from mitochondria to cytosol indicated initiation of early apoptosis in CIN- and EUG-treated C. glabrata cells. Transcriptional analysis showed that multidrug transporter ( CDR1 ) and ergosterol biosynthesis genes were downregulated in the presence of CIN, while getting upregulated in EUG-treated cells. Interestingly, genes such as 1,3-β-glucan synthase ( FKS1 ), GPI-anchored protein ( KRE1 ), and sterol importer ( AUS1 ) were downregulated upon treatment of CIN/EUG. These results provided molecular-level insights about the antifungal mechanism of CIN and EUG against C. glabrata including its resistant clinical isolate. The current data established that CIN and EUG can be potentially formulated in new antifungal strategies.

Antifungal Activity of the Natural Coumarin Scopoletin Against Planktonic Cells and Biofilms From a Multidrug-Resistant Candida tropicalis Strain

“…OD at 530 nm was measured at 0 and 48 h after incubation. The proportion of the inhibition of biofilm proliferation was based on the reduction between the OD at 48 h and the OD at 0 h, as following: [(ODr control) -(ODr treated)/(ODr control)], where ODr = [OD at 48 h-OD at 0 h] (Gupta et al, 2018). The experiments were performed in triplicate.…”

“…Coumarins represent a diverse group of natural polyphenols found in a variety of plants and known by their varied pharmacological properties (Reviewed in Kostova et al, 2011 ; Pinto and Silva, 2017 ; Tomasz Kubrak et al, 2017 ). Scopoletin is one type of coumarin with promising biological activities including antioxidant ( Jamuna et al, 2015 ; Zhang et al, 2017 ), anti-inflammatory ( Jamuna et al, 2015 ; Leema and Tamizhselvi, 2018 ), anti-aging ( Jamuna et al, 2015 ) and anti-tumoral ( Pinto and Silva, 2017 ; Gupta et al, 2018 ) effects.…”

Plant-Derived Substances in the Fight Against Infections Caused by Candida Species

“…An interesting report with terpene cinnamaldehyde showed its fungicidal activity against C. glabrata isolates, demonstrating reduced expression of the FKS1 gene responsible for β-1,3-glucan biosynthesis. However, in that study, the content of extracellular carbohydrates was actually observed to increase [ 89 ]. On the other hand, a different course of action for β-1,3-glucan reduction by poacic acid was reported in several Candida spp.…”

“…On the other hand, essential oils of Cinnamomum verum and Pelargonium graveolens rich in terpenes and phenylpropanoids were able to act synergistically with fluconazole, resulting in membrane destabilization due to reduced ergosterol biosynthesis and disturbed fatty acid homeostasis in C. albicans cells [ 96 ]. Gupta and co-workers [ 89 ] also demonstrated the reduction of ergosterol synthesis in C. glabrata isolates by another terpene–cinnamaldehyde, due to a decreased expression of gene encoding enzymes involved in ergosterol synthesis in the cell membrane ( ERG2, ERG3, ERG4, ERG10, ERG11 ) and gene encoding ABC transporters ( CDR1 ).…”

“…Cinnamaldehyde―a phenylpropanoid mentioned above for its anticandidal activity, also induces pro-apoptotic processes. It was demonstrated that wild and isolated strains of C. albicans [ 124 ] and C. glabrata [ 89 ] treated with cinnamaldehyde presented increased ROS production and increased release of cytochrome C from mitochondria. Further effects observed in that study included an enhanced calcium concentration in the cytoplasm and mitochondria, activation of metacaspase, DNA damage, and chromatin condensation when membrane phosphatidylserine was exposed [ 124 ].…”