Feasibility study on biostimulation of dye decolorization and bioelectricity generation by using decolorized metabolites of edible flora-extracts

Interactive network pharmacology and electrochemical analysis reveals electron transport-mediating characteristics of Chinese medicine formula Jing Guan Fang

Background

Jing Guan Fang (JGF) is an anti-COVID-19 Chinese Medicine decoction comprised of five medicinal herbs to possess anti-inflammatory and antiviral properties for treatment. This study aims to electrochemically decipher the anti-coronavirus activity of JGF and show that microbial fuel cells may serve as a platform for screening efficacious herbal medicines and providing scientific bases for the mechanism of action (MOA) of TCMs.

Methods

Electrochemical techniques (e.g., cyclic voltammetry) and MFCs were adopted as the bioenergy-based platforms to assess the bioenergy-stimulating characteristics of JGF. Phytochemical analysis correlated polyphenolic and flavonoid content with antioxidant activity and bioenergy-stimulating properties. Network pharmacology on the active compounds was employed to identify anti-inflammatory and anti-COVID-19 protein targets, and molecular docking validated in silico results.

Significant findings

This first-attempt results show that JGF possesses significant reversible bioenergy-stimulation (amplification 2.02 ± 0.04) properties suggesting that its antiviral efficacy is both bioenergy-steered and electron mediated. Major flavonoids and flavone glycosides identified by HPLC (e.g., baicalein and baicalin, respectively) possess electron-shuttling (ES) characteristics that allow herbal medicines to treat COVID-19 via (1) reversible scavenging of ROS to lessen inflammation; (2) inhibition of viral proteins; and (3) targeting of immunomodulatory pathways to stimulate the immune response according to network pharmacology.

Deciphering Electron-Shuttling Characteristics of Neurotransmitters to Stimulate Bioelectricity-Generating Capabilities in Microbial Fuel Cells

This first-attempt study used electrochemical methods to quantitatively assess electron-shuttling capabilities of different neurotransmitters crucial to catecholamine biosynthesis in human brain. As prior studies mentioned, aromatics bearing ortho- or para-dihydroxybenzenes could reveal promising electroactivities to stimulate bioenergy generation in microbial fuel cells (MFCs). This feasibility study extended to investigate the electrochemical characteristics of catecholamines and trace amines (e.g., 14 model compounds selected from neurotransmitters) synthesized by human brain via cyclic voltammetry methods (CVs) and MFCs. Dopamine (DA), levodopa (L-DOPA), epinephrine (EP), norepinephrine (NP), and 3,4-dihydroxyphenylacetic acid (DOPAC) would perform the electron-shuttling characteristics, and the rest would not. In particular, DA formed by decarboxylation of L-DOPA could exhibit relatively higher electrochemical activities than their precursors. In addition, carboxylic acids formed by deamination and carboxylation of trace monoamines would reveal more significant reductive potential (E_pc); however, their oxidative electric currents seemed to be reduced. That is, chemical structure significantly influenced whether the electrochemical characteristics could be effectively expressed. This work also clearly revealed that neurotransmitters with ortho-dihydroxybenzenes exhibited promising stimulation to bioelectricity-generating capabilities of MFCs in the ranking of DA ~ EP > NP > L-DOPA > DOPAC. This was consistent with ES behaviors as CV analyses indicated.

Deciphering optimal biostimulation strategy of supplementing anthocyanin-abundant plant extracts for bioelectricity extraction in microbial fuel cells

BACKGROUND

Microbial fuel cells (MFCs) are effective biofuel devices that use indigenous microbes to directly convert chemical energy from organics oxidation into bioelectric energy. To maximize energy-converting efficiency for bioelectricity generation in MFCs, redox mediators (RMs) (e.g., extracts obtained from plant resource-Camellia green tea) have been explored for optimal stimulation upon electron transfer (ET) capabilities. Anthocyanins are natural antioxidants widely used in food science and medicinal industry. This first-attempt study revealed optimal strategies to augment extracts of anthocyanin-rich herbs (Lycium ruthenicum Murr., Clitoria ternatea Linn. and Vaccinium Spp.) as biofuel sources of catalytic RMs for stimulating bioenergy extraction in MFCs.

RESULTS

This work showed that extracts of anthocyanin-rich herbs were promising electroactive RMs. The maximal power density of MFCs supplemented with extract of L. ruthenicum Murr. was achieved, suggesting that extract of L. ruthenicum Murr. would be the most electrochemically appropriate RMs. Compared to C. ternatea Linn. and Vaccinium Spp., L. ruthenicum Murr. evidently owned the most significant redox-mediating capability to stimulate bioenergy extraction likely due to significantly high contents of polyphenols (e.g., anthocyanin). Evidently, increases in adenosine triphosphate (ATP) content directly responded to supplementation of anthocyanin-rich herbal extracts. It strongly suggested that the electron-shuttling characteristics of RMs upon electroactive microorganisms could effectively promote the electron transfer capability to maximize bioenergy extraction in MFCs.

CONCLUSION

Anthocyanin as the main water-soluble vacuolar pigments in plant products were very electroactive for not only excellent antioxidant activities, but also promising electron-shuttling capabilities for renewable biofuel applications. This work also suggested the electron-shuttling mechanism of RMs that could possibly promote electron transport phenomena through microbial cell membrane, further influencing the electron transport chain for efficient bioenergy generation.

Exploring optimal supplement strategy of medicinal herbs and tea extracts for bioelectricity generation in microbial fuel cells

This first-attempt study used extracts of appropriate antioxidant abundant Camellia and non-Camellia tea and medicinal herbs as model ESs to stably intensify bioelectricity generation performance in microbial fuel cells (MFCs). As electron shuttles (ESs) could stimulate electron transport phenomena by significant reduction of electron transfer resistance, the efficiency of power generation for energy extraction in microbial fuel cells (MFCs) could be appreciably augmented. Using environmentally friendly natural bioresource as green bioresource of ESs is the most promising to sustainable practicability. As comparison of power-density profiles indicated, supplement of Camellia tea extracts would be the most appropriate, then followed non-Camellia Chrysanthemum tea and medicinal herbs. Antioxidant activities, total phenolic contents and power stimulating activities were all electrochemically associated. In particular, the extract of unfermented Camellia tea (i.e., green tea) was the most promising ESs to augment bioenergy extraction compared to other refreshing medicinal herb extracts.