Antibacterial activity of the extracts from the fruit rinds of Garcinia cowa and Garcinia pedunculata against food borne pathogens and spoilage bacteria

A new xanthone from Garcinia cowa Roxb. and its anti-inflammatory activity

ETHNOPHARMACOLOGICAL RELEVANCE

Garcinia cowa Roxb. commonly known as asam kandis in Indonesia and Cha muang in Thailand, has been extensively utilized as traditional medicine. This plant contains compounds such as xanthones, phloroglucinol, depsidones, terpenoids, steroids, and flavonoids. These compounds have been extensively studied for various bioactivities. However, the utilization of this plant as an anti-inflammatory agent is still limited.

AIM OF THE STUDY

This study aims to evaluate newly derived compounds from Garcinia cowa Roxb., focusing on their ADMET profiles (Absorption, Distribution, Metabolism, Excretion, and Toxicity) and anti-inflammatory bioactivity. The assessment will be carried out using a combination of in silico and in vitro experiments to determine their pharmacological potential as anti-inflammatory agents.

MATERIALS AND METHODS

Isolation of compounds from Garcinia cowa Roxb. was carried out using column chromatography, purified with radial chromatography, and recycling HPLC. The compounds' structures were evaluated for their ADMET profiles and anti-inflammatory bioactivity using the NF-ĸB protein (PDB Code: 2RAM) as the target. The in vitro experiment was conducted using Raw 264.7 macrophages cell to assess cytotoxicity, phagocytic activity, IL-6, and TNF-α secretion. The determination of the anti-inflammatory mechanism is carried out by testing the activity of NF-ĸB and IKB-α using the Western blot method.

RESULTS

We successfully analyzed the structure of a new compound from the bark of Garcinia cowa Roxb., named Garciacowanin (NC). In silico analysis suggests that the drug shows promising absorption potential, there are concerns related to its metabolism and toxicity that warrant further investigation during the development process and does not show mutagenic properties based on the negative AMES test results. There is a risk of hepatotoxicity (liver damage) and the drug can also interfere with the hERG II ion channel, which can cause side effects on the heart. The compound can affect the NF-ĸB protein, while in vitro studies have demonstrated its ability to suppress phagocytic activity, as well as the production of IL-6 and TNF-α. Western blot analysis suggests that NC's anti-inflammatory mechanism functions via the NF-ĸB signaling pathway.

CONCLUSION

NC has the potential to be developed as an anti-inflammatory agent with a mechanism of inhibiting the inflammatory response through the NF-ĸB signaling pathway.

A standardized chamuangone enriched extract from Garcinia cowa Roxb. leaves shows acute and sub-acute safety

ETHNOPHARMACOLOGICAL RELEVANCE

The safety assessment of herbal products is critical for their appropriate pharmacological applications. Garcinia cowa Roxb., commonly known as Cha-muang in Thai, has ethnopharmacological relevance for inflammation, infectious diseases, and diabetes. The leaf extracts of G. cowa have been extensively reported for their anticancer, anti-inflammatory, antimicrobial, and antioxidant effects. Notably, chamuangone is their major active constituent that contributes to various pharmacological properties.

AIM OF THE STUDY

The current study aims to establish a standardized chamuangone enriched extract (CEE) and assess its acute and sub-acute toxicities in animal models.

METHODOLOGY

CEE was established from G. cowa leaves using a microwave-assisted extraction (MAE), followed by fractionation and enrichment through silica gel vacuum and column chromatography. The concentration of chamuangone in the extract was quantified using a validated quantitative high-performance liquid chromatography (HPLC) method. The safety profiles of CEE were thoroughly evaluated in rodents according to the Organization for Economic Cooperation and Development (OECD) 425 and 407 guidelines. The effects on oxidative stress markers such as superoxide dismutase (SOD), reduced glutathione (GSH), catalase (CAT), and malondialdehyde (MDA) levels were also evaluated in various organs.

RESULTS

Based on the quantitative HPLC analysis, the CEE contained 73.0 ± 2.0% w/w of chamuangone. In the acute toxicity study, following up and down procedure the female rats were dosed with CEE at 1750 and 550 mg/kg body weight (b.w.), with CEE 1750 mg/kg b.w. was toxic, causing mortality, while CEE 550 mg/kg b.w. was deemed safe. An LD50 value was calculated according to the standard protocols, resulting in 970 mg/kg b.w. In histopathological examination, 550 mg/kg b.w. of CEE was safe in all the selected organs, while the 1750 mg/kg b.w. CEE treated rats exhibited toxic effects in histological tissues sections in the form of necrosis in the brain, cardiac muscle hypertrophy, liver inflammation, mild untoward effect in the spleen, fibrosis in the lungs, pancreatitis, pyelonephritis, and ovarian cyst. Administration of CEE at doses of 550 mg/kg b.w. (single dose) in the acute and 100 mg/kg b.w. (regularly 28-days) in the sub-acute toxicity studies significantly (p < 0.05) decreased levels of uric acid, triglycerides, and cholesterol. Importantly, the CEE (550 and 100 mg/kg b.w.) also significantly increased the levels of antioxidant enzymes (SOD, GSH, and CAT) and decreased MDA levels. Normal histopathology was observed in the sub-acute toxicity study in all treated groups.

CONCLUSION

This study successfully concludes that CEE at a dose of 100 mg/kg b.w. is safe for therapeutic application or use as a chemopreventive functional food utilizing green extraction methods. However, chronic toxicity studies are further recommended to validate safety concerns over an extended period.

Garcinia cowa bark extract induces oxidative stress mediated cellular apoptosis in Leishmania donovani parasite modulated by its active phytosterol constituent

Visceral leishmaniasis still remains a leading cause of parasitic deaths, with modern pentavalent antimonials showing limited efficacy and health risks. The methanolic bark extract of the Northeastern Indian plant, Garcinia cowa, demonstrated potent leishmanicidal effects against the parasite Leishmania donovani, demonstrating IC50 values of 20-36 µg/ml, with selective toxicity for parasites over healthy cells. It induced parasite death through elevated oxidative and nitrosative stress elements, reduced arginase activity, nuclear fragmentation, cell cycle arrest, and apoptosis. A GC-MS study and molecular docking identified stigmasterol as a primary component, an antileishmanial compound that inhibits Leishmania donovani parasite efficiently.

Anti-inflammatory activity of the phenol rich fraction of Garcinia pedunculata Roxb (ex. Buch Ham): an in vitro and in vivo study

Garcinia pedunculata, a tropical plant found abundantly in the north-east region of India, has been used by many traditional healers for various gastrointestinal ailments. Studies are being carried out for the proper pharmacological identification of the compounds as well as the mode of action for the treatment of various diseases. In this study, phytochemistry of the fruit was evaluated, followed by a quantitative analysis of the total phenolic and flavonoid content of the methanolic crude extract as well as different fractions (n-hexane, chloroform, ethyl acetate, and n-butanol). The fraction with the most potent flavonoid and phenolic content was evaluated for its anti-inflammatory activity using both in vitro and in vivo assays. The chloroform fraction of G. pedunculata fruit extract was found to have a substantial amount of phenols and flavonoids. This fraction inhibited the denaturation of BSA and significantly stabilized human RBC membrane compared to the standard drug Diclofenac sodium. The fraction also significantly reduced the formaldehyde-induced paw edema in mice and normalized the blood parameters. This study provides evidence that G. pedunculata fruit extract plays a critical role in anti-inflammatory activity, indicating that it can be a potential candidate for further investigation in the treatment of inflammation-related diseases.

Comprehensive studies of the anti-inflammatory effect of tetraprenyltoluquinone, a quinone from Garcinia cowa Roxb

ETHNOPHARMACOLOGICAL RELEVANCE

Garcinia cowa Roxb. is called asam kandis in West Sumatra. This plant contains several quinone compounds, including tetraprenyltoluquinone (TPTQ). The bioactivity of this compound has been tested as an anticancer agent. However, reports regarding its anti-inflammatory effects are still limited, especially against coronavirus disease (Covid-19).

AIM OF THE STUDY

This study explores the anti-inflammatory effect of TPTQ in silico, in vitro, and in vivo.

MATERIALS AND METHODS

In silico testing used the Gnina application, opened via Google Colab. The TPTQ structure was docked with the nuclear factor kappa B (NF-ĸB) protein (PDB: 2RAM). In vitro testing began with testing the cytotoxicity of TPTQ against Raw 264.7 cells, using the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) method. A phagocytic activity test was carried out using the neutral red uptake method, and interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) secretion tests were carried out using the enzyme-linked immunosorbent assay (ELISA) method. In vivo, tests were carried out on mice by determining cluster of differentiation 8+ (CD8+), natural killer cell (NK cell), and IL-6 parameters, using the ELISA method.

RESULTS

TPTQ has a lower binding energy than the native ligand and occupies the same active site as the native ligand. TPTQ decreased the phagocytosis index and secretion of IL-6 and TNF-α experimentally in vitro. TPTQ showed significant downregulation of CD8+ and slightly decreased NK cells and IL-6 secretion in vivo.

CONCLUSION

The potent inhibitory effect of TPTQ on the immune response suggests that TPTQ can be developed as an anti-inflammatory agent, especially in the treatment of Covid-19.

Effective drying processes for Taikor (Garcinia pedunculata Roxb.) fruit by ultrasound-assisted osmotic pretreatment: Analysis of quality and kinetic models

The present study aimed to analyze and establish an effective combination of ultrasound and immersion pretreatment processes for drying Taikor (Garcinia pendunculata Roxb.) fruits. Taikorslices were first immersed in 10 % sucrose, fructose, and glucose solution. Then, the immersed slices were treated in an ultrasonic bath at 30 °C for 10, 20, and 30 min. Drying operations were carried out at 50, 60, and 70 °C, with a fixed relative humidity of 30 %. The Page, Newton, Henderson and Pabis, and Weibull distribution models were fitted to the obtained drying data to determine the best kinetic model that effectively describes the drying properties ofTaikor. After drying operations, changes in quality parameters, e.g., β-carotene, vitamin C, B vitamins, color, antioxidant activities, and microbial loads, were measured to obtain the best drying temperature and the most effective pretreatment combination with minimum loss of nutrients of the sample. Among different kinetic models, both Page and Weibull distribution models showed the best R2 values of 0.9867 and 0.9366, respectively. The chemical properties were preserved to the greatest extent possible by drying at 50 °C with glucose pretreatment. The color parameters were better preserved by fructose pretreatment. Sonication time also had profound effect on the quality parameters of dried Taikor slices. However, higher temperature drying required a shorter time for drying and exhibited better performance in microbial load reduction. This study's findings will help to establish an effective drying condition forGarcinia pedunculatafruits.

Comprehensive Metabolite Profiling of Two Edible Garcinia Species Based on UPLC-ESI-QTOF-MSE Coupled with Bioactivity Assays

In China, the endemic species Garcinia yunnanensis and native Garcinia xanthochymus are known as edible and medicinal plants. However, a systematic metabolomic and bioactivity evaluation of different plant parts from both species is lacking. In this study, comprehensive investigations of 11 plant parts of G. yunnanensis and 10 of G. xanthochymus employing UPLC-ESI-QTOF-MS^E-based metabolomic analysis in conjunction with three bioactivity assays were undertaken. A customized chemotaxonomic-based in-house library containing 6456 compounds was constructed and coupled to the Progenesis QI informatic platform for metabolite annotations. From these two species, a total of 235 constituents were characterized using multiple criteria. Differences in metabolite profiles between the plant parts within each species were uncovered using multivariate analysis. Based on orthogonal partial least-squares discriminant analysis (OPLS-DA), 23 markers were identified as highly differential metabolites from G. xanthochymus and 20 from G. yunnanensis. Comparative assessment of the biological assays revealed the activity variations among different plant parts. The seeds of both species and G. yunnanensis latex exhibited excellent cytotoxic and antibacterial activities, while G. xanthochymus roots and G. yunnanensis arils showed strong anti-inflammatory effects. S-plot analysis identified 26 potential biomarkers for the observed activities, including the known cytotoxic agent cycloxanthochymol and the anti-inflammatory compound garcimultiflorone B, which likely explains some of the potent observed bioactivity.

A Comprehensive Review of the Phytochemical and Pharmacological Potential of an Evergreen Plant Garcinia cowa

Garcinia cowa of the Clusiaceae family, native to South-East Asia used in traditional medicine. It has antipyretic, antimicrobial, and many other biological activities. In this review, a thorough study of this plant's chemical constituents and pharmacological and therapeutic effects was conducted from the research articles from PubMed, Science Direct, Google Scholar, and Scopus from 1977 to 2022. Reported secondary metabolites are enriched with xanthones, phloroglucinols, depsidones, steroids, etc. α-mangostin, β-mangostin, cowaxanthone, rubraxanthone, cowanin, norcowanin, etc. represent the major xanthones. This article discusses the relationship between the different functional groups in xanthone compounds and their bioactivity against cancer, diabetes, bacteria, leishmania, malaria, and inflammation. This review is a comprehensive compendium of major bioactive molecules and its implication for human disease.

Biphenyls in Clusiaceae: Isolation, structure diversity, synthesis and bioactivity

Clusiaceae plants contain a wide range of biologically active metabolites that have gotten a lot of interest in recent decades. The chemical compositions of these plants have been demonstrated to have positive effects on a variety of ailments. The species has been studied for over 70 years, and many bioactive compounds with antioxidant, anti-proliferative, and anti-inflammatory properties have been identified, including xanthones, polycyclic polyprenylated acylphloroglucinols (PPAPs), benzophenones, and biphenyls. Prenylated side chains have been discovered in many of these bioactive substances. To date, there have been numerous studies on PPAPs and xanthones, while no comprehensive review article on biphenyls from Clusiaceae has been published. The unique chemical architectures and growing biological importance of biphenyl compounds have triggered a flurry of research and interest in their isolation, biological evaluation, and mechanistic studies. In particular, the FDA-approved drugs such as sonidegib, tazemetostat, daclatasvir, sacubitril and trifarotene are closely related to their biphenyl-containing moiety. In this review, we summarize the progress and development in the chemistry and biological activity of biphenyls in Clusiaceae, providing an in-depth discussion of their structural diversity and medicinal potential. We also present a preliminary discussion of the biological effects with or without prenyl groups on the biphenyls.

Antibacterial and Antiviral Properties of Tetrahydrocurcumin-Based Formulations: An Overview of Their Metabolism in Different Microbiotic Compartments

In this review, the basic metabolic characteristics of the curcuminoid tetrahydrocurcumin (THC) at the level of the intestinal microbiota were addressed. Special attention was given to the bactericidal effects of one of the THC-phospholipid formulations, which has shown greater bioavailability and activity than pure THC. Similarly, quinoline derivatives and amino acid conjugates of THC have also shown antibacterial effects in the gut. The microbial effect of pure THC is particularly pronounced in pathophysiological conditions related to the function of the intestinal microbiota, such as type II diabetes. Furthermore, the antiviral characteristics of Cur compared to those of THC are more pronounced in preventing the influenza virus. In the case of HIV infections, the new microemulsion gel formulations of THC possess high retention during preventive application in the vagina and, at the same time, do not disturb the vaginal microbiota, which is critical in maintaining low vaginal pH. Based on the reviewed literature, finding new formulations of THC which can increase its bioavailability and activity and emphasize its antibacterial and antiviral characteristics could be very important. Applying such THC formulations in preventing and treating ailments related to the microbiotic compartments in the body would be beneficial from a medical point of view.

Six new polyoxygenated xanthones from Garcinia cowa and their neuroprotective effects on glutamate-mediated hippocampal neuronal HT22 cell death

Six new polyoxygenated xanthones, garcicowanones F-H (1-3), norcowanol A-B (4-5), and garcinone F (6) along with twelve known compounds 7-18 were obtained from the latex of Garcinia cowa Roxb. ex Choisy. All new compounds have a 1,3,7-trioxygenated or 1,3,6,7-tetraoxygenated xanthone nucleus and differ from majority of xanthones from G. cowa by hydrated side chains. Compounds 1, 7, 8 and 18 exhibited significant neuroprotective effects on glutamate-mediated hippocampal neuronal HT22 cell death. In particular, compound 1 exhibited the most potent neuroprotective effect with >80% cell viability in the concentration range of 2.9-115 µM. Further studies on compound 1 showed that it decreased cellular Ca2+ influx and inhibits cellular reactive oxygen species generation in HT22 cells. A Western blot analysis showed that MAPK phosphorylation, Bax, and AIF translocation dramatically increased upon treatment with 5 mM glutamate and decreased upon a co-treatment with compound 1.

The Potential of α-Mangostin from Garcinia mangostana as an Effective Antimicrobial Agent-A Systematic Review and Meta-Analysis

This systematic review aims to evaluate the antimicrobial activity of α-mangostin derived from Garcinia mangostana against different microbes. A literature search was performed using PubMed and Science Direct until March 2022. The research question was developed based on a PICO (Population, Intervention, Control and Outcomes) model. In this study, the population of interest was microbes, α-mangostin extracted from Garcinia mangostana was used as exposure while antibiotics were used as control, followed by the outcome which is determined by the antimicrobial activity of α-mangostin against studied microbes. Two reviewers independently performed the comprehensive literature search following the predetermined inclusion and exclusion criteria. A methodological quality assessment was carried out using a scoring protocol and the risk of bias in the studies was analyzed. Reward screening was performed among the selected articles to perform a meta-analysis based on the pre-determined criteria. Case groups where α-mangostin extracted from Garcinia mangostana was incorporated were compared to groups using different antibiotics or antiseptic agents (control) to evaluate their effectiveness. A total of 30 studies were included; they were heterogeneous in their study design and the risk of bias was moderate. The results showed a reduction in microbial counts after the incorporation of α-mangostin, which resulted in better disinfection and effectiveness against multiple microbes. Additionally, the meta-analysis result revealed no significant difference (p > 0.05) in their effectiveness when α-mangostin was compared to commercially available antibiotics. α-mangostin worked effectively against the tested microbes and was shown to have inhibitory effects on microbes with antibiotic resistance.

Antibacterial Activity and Phytochemical Screening of Garcinia pedunculata Roxb. ex Buch. - Ham. fruit extract by HPLC–ESI-MS

Disc and well diffusion methods were used to test the antibacterial activity of methanol extract and ethanol extract of the selected ethnomedicinal plant viz. Garcinia pedunculata Roxb. ex Buch.-Ham. Both the methanol extract and ethanol extract were subjected to antibacterial activity assay against the six clinical isolates. Antibiotic sensitivity test of the test bacteria against standard antibiotics were also determined. All the bacterial pathogens (Staphylococcus aureus, Enterococcus faecalis, Enterobacter cloacae, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae) were exposed to the plant extract in triplicates. The investigation revealed the potency of G. pedunculata extract as an effective antibacterial agent against both Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB). G. pedunculata are evaluated to be bactericidal against the tested bacteria. The antibacterial activity may be due to an individual compound or synergistic effect of more than one compound present in the medicinal plant extract. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of the plant extracts were also investigated by using the broth microdilution method. HPLC-MS of the methanol extract of G. pedunculata fruit revealed the presence of Hydroxy Citric Acid Lactone (MW-190), Garcinone-E (MW-464), a-Mangostin (MW-410), β–Mangostin (MW-424), and γ-Mangostin (MW-396).

Anti-inflammatory xanthone derivatives from Garcinia delpyana

Two new xanthones delpyxanthone A (1) and delpyxanthone B (3), together with four known ones, gerontoxanthone I (2), α-mangostin (4), cowanin (5) and cowanol (6) were isolated from the stem bark of Garcinia delpyana. The chemical structures of 1-6 were established mainly using nuclear magnetic resonance (NMR) and mass spectrometry (MS). The anti-inflammatory activity of the isolated compounds was evaluated against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 cells in vitro. Compounds 1-4 showed significant inhibitory activity against the LPS-induced NO production in RAW264.7 cells with IC₅₀ values ranging from 14.5 to 28.2 μM, but the others were inactive. The results suggested that G. delpyana and its constituents might be potential anti-inflammatory agents on RAW 264.7 cells.[Formula: see text].

DNA Repair Biosensor-Identified DNA Damage Activities of Endophyte Extracts from Garcinia cowa

Recent developments in chemotherapy focus on target-specific mechanisms, which occur only in cancer cells and minimize the effects on normal cells. DNA damage and repair pathways are a promising target in the treatment of cancer. In order to identify novel compounds targeting DNA repair pathways, two key proteins, 53BP1 and RAD54L, were tagged with fluorescent proteins as indicators for two major double strand break (DSB) repair pathways: non-homologous end-joining (NHEJ) and homologous recombination (HR). The engineered biosensor cells exhibited the same DNA repair properties as the wild type. The biosensor cells were further used to investigate the DNA repair activities of natural biological compounds. An extract from Phyllosticta sp., the endophyte isolated from the medicinal plant Garcinia cowa Roxb. ex Choisy, was tested. The results showed that the crude extract induced DSB, as demonstrated by the increase in the DNA DSB marker γH2AX. The damaged DNA appeared to be repaired through NHEJ, as the 53BP1 focus formation in the treated fraction was higher than in the control group. In conclusion, DNA repair-based biosensors are useful for the preliminary screening of crude extracts and biological compounds for the identification of potential targeted therapeutic drugs.

Medicinal Potential of Garcinia Species and Their Compounds

Garcinia is a genus of Clusiaceae, distributed throughout tropical Asia, Africa, New Caledonia, Polynesia, and Brazil. Garcinia plants contain a broad range of biologically active metabolites which, in the last few decades, have received considerable attention due to the chemical compositions of their extracts, with compounds which have been shown to have beneficial effects in several diseases. Our work had the objective of reviewing the benefits of five Garcinia species (G. brasiliensis, G. gardneriana, G. pedunculata, G. cambogia, and G. mangstana). These species provide a rich natural source of bioactive compounds with relevant therapeutic properties and anti-inflammatory effects, such as for the treatment of skin disorders, wounds, pain, and infections, having demonstrated antinociceptive, antioxidant, antitumoral, antifungal, anticancer, antihistaminic, antiulcerogenic, antimicrobial, antiviral, vasodilator, hypolipidemic, hepatoprotective, nephroprotective, and cardioprotective properties. This demonstrates the relevance of the genus as a rich source of compounds with valuable therapeutic properties, with potential use in the prevention and treatment of nontransmissible chronic diseases.

Melanosis and quality changes during refrigerated storage of Pacific white shrimp treated with Chamuang (Garcinia cowa Roxb.) leaf extract with the aid of pulsed electric field

Pacific white shrimp with prior pulsed electric field (PEF) treatment before soaking in Chamuang leaf extract (CLE) at different concentrations (0.5 and 1%) for 30 min were prepared. Sample pre-treated with PEF and soaked with 1% CLE (PEF-1 CLE) showed lower melanosis score than that with 1.25% sodium metabisulfite treatment, PEF treated sample or those soaked in CLE without prior PEF and the control during storage of 10 days (P < 0.05). PEF-1 CLE sample showed lower total volatile base content, peroxide value and thiobarbituric acid reactive substances but high sensory scores than others (P < 0.05). Lower increases in mesophile, psychrophile, Pseudomonas, Enterobacteriaceae and H₂S producing bacterial counts were obtained in PEF-1 CLE, compared to the control and other treated samples. The most abundant compounds from Chamuang leaf extract, including Chrysoeriol 6-C-glucoside-8-C-arabinopyranoside and veranisatin-C were found in PEF-1 CLE sample and were plausibly involved in keeping quality of shrimp.

Investigation on the Antibacterial and Anti-T3SS Activity of Traditional Myanmar Medicinal Plants

Myanmar has a rich pool of, but less known, medicinal plants with traditional knowledge. In this study, we aimed to investigate the inhibitory activity of traditional Myanmar medicinal plants against the type III secretion system (T3SS) of Salmonella enterica serovar Typhimurium UK-1 χ8956 and the intestinal disease-caused by microbes including S. enterica serovar Typhimurium UK-1 χ8956, Proteusbacillus vulgaris CPCC 160013, Escherichia coli CICC 10003, and Staphylococcus aureus ATCC 25923. The EtOH extracts of 93 samples were used to screen the inhibitory activities against the secretion of T3SS effector proteins SipA/B/C/D of S. enterica and the antibacterial activity against S. enterica, P. vulgaris, E. coli, and S. aureus. Out of 71 crude drugs traditionally used, 18 were proofed to be effective either on the growth inhibition of tested bacteria and/or as inhibitors for the T3SS. The EtOH extracts of five plants, Luvunga scandens (Roxb.) Buch.-Ham. ex Wight & Arn. (My7), Myrica nagi Thunb. (My11), Terminalia citrina Roxb. ex Fleming (My21), Thymus vulgaris L. (My49), and Cinnamomum bejolghota (Buch.-Ham.) Sweet (My104), showed potent inhibitory activities against the secretion of T3SS proteins SipA/B/C/D of S. enterica serovar Typhimurium UK-1 χ 8956. Mansonia gagei J.R.Drumm (My3) and Mesua ferrea (Roxb.) L. (My10) showed strong antibacterial activities against P. vulgaris and S. aureus. This study provided the first scientific evidence of T3SS prohibiting and antibacterial properties for the traditional knowledge in Myanmar of using plants as medicines for treating infections and gastrointestinal disease. Further researches are proposed to discover the active chemical compounds and mechanism of L. scandens (Roxb.) Buch.-Ham. ex Wight & Arn, M. nagi Thunb., T. citrina Roxb. ex Fleming, T. vulgaris L., and C. bejolghota (Buch.-Ham.) Sweet as antivirulence drugs and the potential of M. gagei J.R.Drumm and M. ferrea L. as new broad spectrum plant antibiotics.

Antihyperglycemic, Antidiabetic, and Antioxidant Effects of Garcinia pedunculata in Rats

The antihyperglycemic, antidiabetic, and antioxidant potentials of the methanolic extract of Garcinia pedunculata (GP) fruit in rats were investigated. The acute antihyperglycemic effect of different doses of GP was studied in normal male Wistar rats. Diabetes was induced by streptozotocin (STZ) injection in another cohort of male Wistar rats and they showed significantly higher blood glucose and glycated hemoglobin (HbA1c) levels, altered lipid profiles, and lower insulin levels compared to nondiabetic control animals. There were increased lipid peroxidation and reduced levels of cellular antioxidant enzymes in different tissues of diabetic rats. However, oral administration of GP extracts, especially the highest dose (1000 mg/kg), significantly ameliorated hyperglycemia (42%); elevated insulin levels (165%); decreased HbA1c (29.4%); restored lipid levels (reduction in TG by 25%, TC by 15%, and LDL-C by 75% and increase in HDL-C by 4%), liver and renal function markers, and lipid peroxidation (reduction by 52% in the liver, 39% in the kidney, 44% in the heart, and 46% in the pancreas); and stimulated tissue antioxidant enzymes to near normalcy. Overall, the findings suggest that GP fruit is effective against hyperglycemia and could be used in the treatment of diabetes and its complications and other oxidative stress-mediated pathological conditions.

In vitro assessment of anti-proliferative effect induced by α-mangostin from Cratoxylum arborescens on HeLa cells

Natural medicinal products possess diverse chemical structures and have been an essential source for drug discovery. Therefore, in this study, α-mangostin (AM) is a plant-derived compound was investigated for the apoptotic effect on human cervical cancer cells (HeLa). The cytotoxic effects of AM on the viability of HeLa and human normal ovarian cell line (SV40) were evaluated by using MTT assay. Results showed that AM inhibited HeLa cells viability at concentration- and time-dependent manner with IC₅₀ value of 24.53 ± 1.48 µM at 24 h. The apoptogenic effects of AM on HeLa were assessed using fluorescence microscopy analysis. The effect of AM on cell proliferation was also studied through clonogenic assay. ROS production evaluation, flow cytometry (cell cycle) analysis, caspases 3/7, 8, and 9 assessment and multiple cytotoxicity assays were conducted to determine the mechanism of cell apoptosis. This was associated with G2/M phase cell cycle arrest and elevation in ROS production. AM induced mitochondrial apoptosis which was confirmed based on the significant increase in the levels of caspases 3/7 and 9 in a dose-dependent manner. Furthermore, the MMP disruption and increased cell permeability, concurrent with cytochrome c release from the mitochondria to the cytosol provided evidence that AM can induce apoptosis via mitochondrial-dependent pathway. AM exerted a remarkable antitumor effect and induced characteristic apoptogenic morphological changes on HeLa cells, which indicates the occurrence of cell death. This study reveals that AM could be a potential antitumor compound on cervical cancer in vitro and can be considered for further cervical cancer preclinical and in vivo testing.

Assessment of Toxicity and Beneficiary Effects of Garcinia pedunculata on the Hematological, Biochemical, and Histological Homeostasis in Rats

This study was undertaken to investigate the toxicological profile of a methanolic extract of Garcinia pedunculata fruit in rats by conducting hematological, biochemical, and histopathological examinations. Long Evans rats were divided into four groups, each with 6 animals, and were treated with three oral doses (250, 500, and 1000 mg/kg) once daily for 21 days. The extract did not cause significant changes in body and relative organ weight, percent water content, or hematological parameters at any administered doses. However, a significant dose-dependent positive effect in serum lipid profile and all atherogenic indices including the cardiac risk ratio, Castelli's risk index-2, and the atherogenic coefficient were observed. Significant increases in the levels of iron and decreases in serum alkaline phosphatase, alanine transaminase, and lactate dehydrogenase activities and the levels of serum glucose were noted when the extract was administered at the highest dose (1000 mg/kg). Histopathological examination of the target tissues further confirmed that the extract was safe and had no observed toxicological features. Our study indicates that G. pedunculata fruit is nontoxic, has the potential to be effective against atherosclerosis, and may be used as a hepatoprotectant. The fruit extract is also beneficial to those with iron deficiency and hyperglycemia.

Bioactive prenylated xanthones from the young fruits and flowers of Garcinia cowa

Five new xanthones, garciniacowones A-E (1-5), together with 14 known xanthones, 6-19, were isolated from the young fruits and fresh flowers of Garcinia cowa. The structures of 1-5 were elucidated by analysis of their 1D and 2D NMR spectra and mass spectrometric data. The compounds 1-19 were tested in vitro for their antimicrobial activity and for their ability to inhibit α-glucosidase. Compounds 16 and 17 showed the most potent α-glucosidase inhibitory activity, with IC50 values of 7.8 ± 0.5 and 8.7 ± 0.3 μM, respectively. Compounds 8, 9, and 19 showed antibacterial activity against Bacillus subtilis TISTR 088 with identical MIC values of 2 μg/mL, while 8, 10, and 19 exhibited antibacterial activity against Bacillus cereus TISTR 688 with identical MIC values of 4 μg/mL.

Applications of flow cytometry to characterize bacterial physiological responses

Although reports of flow cytometry (FCM) applied to bacterial analysis are increasing, studies of FCM related to human cells still vastly outnumber other reports. However, current advances in FCM combined with a new generation of cellular reporter probes have made this technique suitable for analyzing physiological responses in bacteria. We review how FCM has been applied to characterize distinct physiological conditions in bacteria including responses to antibiotics and other cytotoxic chemicals and physical factors, pathogen-host interactions, cell differentiation during biofilm formation, and the mechanisms governing development pathways such as sporulation. Since FCM is suitable for performing studies at the single-cell level, we describe how this powerful technique has yielded invaluable information about the heterogeneous distribution of differently and even specialized responding cells and how it may help to provide insights about how cell interaction takes place in complex structures, such as those that prevail in bacterial biofilms.

Prevention of cardiotoxicity of aflatoxin B1 via dietary supplementation of papaya fruit extracts in rats

The aim of the current study was to evaluate the cardioprotective ability of water (WE) and ethanolic (EE) papaya fruits extracts against cardiotoxicity induced by aflatoxin B1 (AFB1) in rats. Forty two female Sprague-Dawley rats were divided into six treatment groups and treated orally for 2 weeks as follow: control group, the group treated with WE (250 mg/kg b.w), the group treated with EE (250 mg/kg b.w), the group treated orally with AFB1 (17 μg/kg b.w) and the groups treated orally with AFB1 plus WE or EE. The results indicated that treatment with AFB1 resulted in oxidative stress in the heart manifested by the marked increase in cardiac malondialdehyde and calcium levels accompanied with a significant decrease in cardiac total antioxidant capacity. Serum nitric oxide and sodium levels, lactate dehydrogenase and creatine kinase isoenzyme activities were significantly increased, whereas, cardiac Na(+)/K(+)-ATPase activity and serum potassium were insignificantly affected. Supplementation with WE or EE effectively ameliorated most of the changes induced by AFB1. It could be concluded that both extracts attenuated the oxidative stress induced in heart tissue by AFB1 and WE was more pronounced due to the higher total phenolic contents than in the EE.

Synthesis and characterization of some bi, tri and tetravalent transition metal complexes of N'-(furan-2-yl-methylene)-2-(p-tolylamino)acetohydrazide HL1 and N'-(thiophen-2-yl-methylene)-2-(p-tolylamino)acetohydrazide HL2

The tetradentate Schiff bases hydrazone ligands HL(1), HL(2) and their metal complexes have been prepared and characterized by analytical, spectral (IR, UV-vis, (1)H NMR and ESR), molar conductivity, magnetic and TGA measurements. The results show that all the metal complexes are non-electrolytes, except (2, 10 and 20) which have ionic nature. The ligands coordinate in keto-neutral form and act as bidentate or tridentate for all metal complexes, except complexes (4 and 12). The ligands react as monobasic tetradentate and tridentate for complexes (4 and 12), respectively. Octahedral/tetrahedral Co(II) and Ni(II), octahedral/square planar Cu(II), and octahedral Mn(II), Fe(III), Cr(III), Ru(III), Hf(IV) and Zr(IV)O geometries were proposed. The ESR spectra of copper complexes (12 and 14) indicate d(x2-y2) ground state with covalent bond character. The thermal decomposition and the types of crystallized water for some metal complexes were studied. The studied metal complexes are very weakly active against the tested microorganisms.

Variation of antioxidant activity and the levels of bioactive compounds in lipophilic and hydrophilic extracts from hot pepper (Capsicum spp.) cultivars

Peppers (Capsicum spp.) are a rich source of diverse bioactive compounds with potential health-promoting properties. This study investigated the extraction efficiency of five solvents on antioxidant activities from cayenne (CA408 and Mesilla), jalapeño (Ixtapa) and serrano (Tuxtlas) pepper cultivars. Freeze-dried peppers were extracted using a Soxhlet extractor with five solvents: hexane, ethyl acetate, acetone, methanol, and methanol:water (80:20). The levels of specific bioactive compounds (phenolics, capsaicinoids, carotenoids and flavonoids) were determined by HPLC and antioxidant activities were assayed by three methods. For all pepper cultivars tested, hexane extracts had the highest levels of capsaicinoids and carotenoids, but methanol extracts had the maximum levels of flavonoids. Hexane extracts showed higher 2,2-diphenyl-1-pricrylhydrozyl (DPPH) radical-scavenging activity and higher reducing power, and acetone extracts (from Mesilla pepper) had a high reducing power. All pepper extracts, except hexane, were effective in preventing deoxyribose degradation, and the inhibition was increased by high concentrations of extracts. The results of the present study indicated that, among the different measures of antioxidant activity, DPPH radical-scavenging activity was strongly correlated with total bioactive compounds (capsaicinoids, carotenoids, flavonoids and total phenolics) in pepper cultivars.

Plant extracts for the control of bacterial growth: efficacy, stability and safety issues for food application

The microbial safety of foods continues to be a major concern to consumers, regulatory agencies and food industries throughout the world. Many food preservation strategies have been used traditionally for the control of microbial spoilage in foods but the contamination of food and spoilage by microorganisms is a problem yet to be controlled adequately. Although synthetic antimicrobials are approved in many countries, the recent trend has been for use of natural preservatives, which necessitates the exploration of alternative sources of safe, effective and acceptable natural preservatives. Plants contain innumerable constituents and are valuable sources of new and biologically active molecules possessing antimicrobial properties. Plants extracts either as standardized extracts or as a source of pure compounds provide unlimited opportunities for control of microbial growth owing to their chemical diversity. Many plant extracts possess antimicrobial activity against a range of bacteria, yeast and molds, but the variations in quality and quantity of their bioactive constituents is the major detriments in their food use. Further, phytochemicals added to foods may be lost by various processing techniques. Several plant extracts or purified compounds intended for food use have been consumed by humans for thousands of years, but typical toxicological information is not available for them. Although international guidelines exist for the safety evaluation of food additives, owing to problems in standardization of plant extracts, typical toxicological values have not been assigned to them. Development of cost effective isolation procedures that yield standardized extracts as well as safety and toxicology evaluation of these antimicrobials requires a deeper investigation.

Antibacterial activity of Alpinia galanga (L) Willd crude extracts

Methanol, acetone and diethyl ether extracts of Alpinia galanga have been evaluated against pathogens viz. Bacillus subtilis MTCC 2391, Enterobacter aerogene, Enterobacter cloacae, Enterococcus faecalis, Escherichia coli MTCC 1563, Klebsiella pneumoniae, Pseudomonas aeruginosa MTCC 6642, Salmonella typhimurium, Staphylococcus aureus and Streptococcus epidermis using Agar well diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of all the extracts were determined using the macrodilution method. Methanol extracts have shown excellent activity towards all the pathogens with MIC and MBC values ranging from 0.04-1.28 mg/ml and 0.08-2.56 mg/ml, respectively. The GC-MS analysis of methanol extracts have yielded compounds like 5-hydroxymethyl furfural (59.9%), benzyl alcohol (57.6%), 1,8 cineole (15.65%), methylcinnamate (9.4%), 3-phenyl-2-butanone (8.5%) and 1,2 benzenedicarboxylic acid (8.9%), which could be responsible for its broad spectrum activity. So, A. galanga can be quite resourceful for the development of new generation drugs.