6-Gingerol inhibits fungal alpha amylase: Enzyme kinetic and molecular modeling studies

Carboxylic acid derivatives suppress the growth of Aspergillus flavus through the inhibition of fungal alpha-amylase

Aspergillus favus (A. flavus) is a saprophytic fungus and a pathogen affecting several important foods and crops, including maize. A. flavus produces a toxic secondary metabolite called aflatoxin. Alpha-amylase (α-amylase), a hydrolytic enzyme produced by A. Flavus helps in the production of aflatoxin by hydrolysing the starch molecules in to simple sugars such as glucose and maltose. These simple sugars induce the production of aflatoxin. Inhibition of α-amylase has been proven as a potential way to reduce the production of aflatoxin. In the present study, we investigated the effect of selected carboxylic acid derivatives such as cinnamic acid (CA), 2, 4-dichlorophenoxyacetic acid (2,4-D), and 3-(4-hydroxyphenyl)-propionic acid (3,4-HPPA) on the fungal growth and for the α-amylase inhibitory activity. The binding potentials of these compounds with α-amylase have been confirmed by enzyme kinetics and isothermal titration calorimetry. Molecular docking and MD simulation studies were also performed to deduce the atomic level interaction between the protein and selected ligands. The results indicated that CA, 2,4-D and 3,4-HPPA can inhibit the fungal growth which could be partly due to the inhibition on fungal α-amylase activity.Communicated by Ramaswamy H. Sarma.

Supplementation of ginger root extract into broiler chicken diet: effects on growth performance and immunocompetence

Ginger contains bioactive compounds that possess anti-inflammatory and antimicrobial properties. In this study, 432-day-old Ross 708 broiler male chicks were randomly allocated to 6 dietary treatments to investigate the effect of ginger root extract (GRE) on immunocompetence and growth performance to 6 wk of age. Treatment 1 (CON) consisted of chicks fed a corn-soybean meal (SBM), a base diet without GRE. Treatment 2 (MX) chicks were given basal diets containing bacitracin methylene disalicylate (BMD) at 0.055 g/kg. Treatments 3 (GRE-0.375%), 4 (GRE-0.75%), 5 (GRE-1.5%), and 6 (GRE-3%) were fed similar diet to control with GRE supplemented at 0.375%, 0.75%, 1.5%, and 3%, respectively. Moreover, HPLC analysis of GRE was carried out to determine the concentration of bioactive compounds found in GRE. Each treatment consisted of 6 replicate pens with 12 chicks/pen. Bodyweight (BW) and feed conversion ratio (FCR) were recorded. Results show that the concentration of bioactive compounds increased with increasing GRE supplementation. Likewise, dietary GRE supplementation did not have any detrimental effect on growth performance parameters up to 1.5%, as values for BWG was not different from CON and MX; however, 3% GRE had the poorest FCR and a lower BWG as compared to other treatments. On d 27 and d 41, fecal and cecal concentrations of total bacteria count (TBC), Escherichia coli, Lactobacillus spp., and Bifidobacterium spp enumerated using selective plating media showed that GRE supplementation significantly reduced (P < 0.05) the amount of TBC and E. coli but increased the number of beneficial microorganisms such as Lactobacillus spp. and Bifidobacterium spp. On d 20, no significant differences were observed (P > 0.05) among all treatments for antibody titer against Newcastle disease virus and total IgY antibodies; however, on d 27, GRE-0.75% had the highest value for both immune indicators and was not different from MX. Dietary supplementation of GRE up to 1.5% enhanced the immune system and suppressed E. coli while promoting the growth of healthy bacteria, without any detrimental effect on growth performance.

Impact of drying and extractions processes on the recovery of gingerols and shogaols, the main bioactive compounds of ginger

Ginger extracts have anti-inflammatory, antioxidant, antitumor, and antibacterial activities mainly due to gingerols and shogaols. Extract composition and functionality can be affected by drying and extraction processes. Alternative methods to obtain ginger extracts based on high contents of gingerols and shogaols have been reported. However, there were no studies that present a broad overview of how these methods affect the composition and functionalities of ginger extracts. Based on literature data from 2011 to 2022, this review shows how drying, extraction, and complementary processes (i.e., enzymatic, acidic, and carbonic maceration) affect the composition and bioactivity of the ginger extract. Lower temperature processes, including freeze-drying, cold ultrasound-, or enzyme-assisted extraction, lead to extracts richer in phenolics, gingerols, and antioxidant activity. On the other hand, acidic solvents or "hot" processes including microwave-drying, pressurized liquid, and microwave-assisted extraction can favor higher shogaols concentrations, which have higher antitumor, anti-inflammatory, and antimicrobial activities than the gingerols precursors. Thus, in this review, we analyzed and discussed the relation between ginger processing and their bioactive compounds, focusing especially on gingerols and shogaols, as well as the main processes that increase the content of 6-shogaol without compromising other phenolic compounds to produce highly functional extracts for future applications in the food packaging sector.

Chemometric study on the biochemical marker of the manglicolous fungi to illustrate its potentiality as a bio indicator for heavy metal pollution in Indian Sundarbans

The study represents in vitro chemometric approach for assessing the heavy metal pollution in Indian Sundarbans. Physio-chemical and elemental characterisation of the sediment samples of Indian Sundarbans had shown high enrichments of toxic metal ions. It was characterised by elevated enrichment factors (2.16-10.12), geo-accumulation indices (0.03 -1.21), contamination factors (0.7-3.43) and pollution load indices (1.0-1.25) which showed progressive sediment quality deterioration and ecotoxicological risk due to metal ions contamination. The physio-chemical parameters of the sediments were replicated and computational chemometric modeling was utilized to assess fungal metabolic growth. All the fungi isolates had shown maximum metabolic activity in high temperature, alkaline pH, and high salinity. Further, the fungal metabolic activity was assessed in different gradient of heavy metal concentration. The significant deterioration of biochemical marker with increasing concentration of heavy metal indicates the status of the microbial health due to toxic metal pollution in the mangrove habitat.

Gingerols and shogaols: Important nutraceutical principles from ginger

Gingerols are the major pungent compounds present in the rhizomes of ginger (Zingiber officinale Roscoe) and are renowned for their contribution to human health and nutrition. Medicinal properties of ginger, including the alleviation of nausea, arthritis and pain, have been associated with the gingerols. Gingerol analogues are thermally labile and easily undergo dehydration reactions to form the corresponding shogaols, which impart the characteristic pungent taste to dried ginger. Both gingerols and shogaols exhibit a host of biological activities, ranging from anticancer, anti-oxidant, antimicrobial, anti-inflammatory and anti-allergic to various central nervous system activities. Shogaols are important biomarkers used for the quality control of many ginger-containing products, due to their diverse biological activities. In this review, a large body of available knowledge on the biosynthesis, chemical synthesis and pharmacological activities, as well as on the structure-activity relationships of various gingerols and shogaols, have been collated, coherently summarised and discussed. The manuscript highlights convincing evidence indicating that these phenolic compounds could serve as important lead molecules for the development of therapeutic agents to treat various life-threatening human diseases, particularly cancer. Inclusion of ginger or ginger extracts in nutraceutical formulations could provide valuable protection against diabetes, cardiac and hepatic disorders.

A lectin from Spatholobus parviflorus inhibits Aspergillus flavus α-amylase: enzyme kinetics and thermodynamic studies

Aspergillus flavus is a commonly found fungal pathogen which produces structurally related and highly toxic secondary metabolites, aflatoxins. It has been proposed that α-amylase inhibitors may limit the ability of the fungus to produce aflatoxins. Hence, this enzyme is a potent target for the development of antifungal agents. In this study, it was found that Spatholobus parviflorus seed lectin (SPL) can inhibit the growth of A. flavus with a MIC value of 1.5 mg/mL. The enzyme kinetics, molecular modeling and isothermal titration calorimetric studies suggest that SPL can inhibit α-amylase with Ki value of 0.0042 mm. Hence, it is suggested that the antifungal activity of SPL might be partly due to its ability to inhibit the enzyme α-amylase.

UBL1 of Fusarium verticillioides links the N-end rule pathway to extracellular sensing and plant pathogenesis

Fusarium verticillioides produces fumonisin mycotoxins during colonization of maize. Currently, molecular mechanisms underlying responsiveness of F.verticillioides to extracellular cues during pathogenesis are poorly understood. In this study, insertional mutants were created and screened to identify genes involved in responses to extracellular starch. In one mutant, the restriction enzyme-mediated integration cassette disrupted a gene (UBL1) encoding a UBR-Box/RING domain E3 ubiquitin ligase involved in the N-end rule pathway. Disruption of UBL1 in F.verticillioides (Δubl1) influenced conidiation, hyphal morphology, pigmentation and amylolysis. Disruption of UBL1 also impaired kernel colonization, but the ratio of fumonisin B1 per unit growth was not significantly reduced. The inability of a Δubl1 mutant to recognize an N-end rule degron confirmed involvement of UBL1 in the N-end rule pathway. Additionally, Ubl1 physically interacted with two G protein α subunits of F.verticillioides, thus implicating UBL1 in G protein-mediated sensing of the external environment. Furthermore, deletion of the UBL1 orthologue in F.graminearum reduced virulence on wheat and maize, thus indicating that UBL1 has a broader role in virulence among Fusarium species. This study provides the first linkage between the N-end rule pathway and fungal pathogenesis, and illustrates a new mechanism through which fungi respond to the external environment.