1. The effect of flavonoids on coumarin 7-hydroxylation, an activity marker of an important human liver cytochrome P450 isoform, cytochrome P450 2A6 (CYP2A6), was investigated in this study. 2. Coumarin 7-hydroxylase activity was measured fluorometrically in reaction mixtures containing cDNA-expressed CYP2A6, nicotinamide adenine dinucleotide phosphate generating system and 10 uM coumarin, at various concentrations of flavonoids. 3. Among the 23 compounds tested, most of the active members were from flavonol group of hydroxylated flavonoids, with myricetin being the most potent inhibitor followed by quercetin, galangin, and kaempferol. 4. Further exploration of the inhibition mechanism of these compounds revealed that myricetin, galangin, and kaempferol exhibited mixed-type of inhibition pattern while quercetin was observed to exhibit competitive mode of inhibition. 5. Structure-function analyses revealed that degree of inhibition was closely related to the number and location of hydroxyl groups, glycosylation of the free hydroxyl groups, degree of saturation of the flavane nucleus as well as the presence of the alkoxylated function.
Tiger's milk mushroom is known for its valuable medicinal properties, especially the tuber part. However, wild tuber is very hard to obtain as it grows underground. This study first aimed to cultivate tiger's milk mushroom tuber through a cultivation technique, and second to compare nutritional and mycochemical contents, antioxidant and cytotoxic activities and compound screening of the cultivated tuber with the wild tuber. Results showed an increase in carbohydrate content by 45.81% and protein content by 123.68% in the cultivated tuber while fat content reduced by 13.04%. Cultivated tuber also showed an increase of up to 64.21% for total flavonoid-like compounds and 62.51% of total β-D-glucan compared to the wild tuber. The antioxidant activity of cultivated tuber and wild tuber was 760 and 840 µg mL-1, respectively. The cytotoxic activity of boiled water extract of cultivated tuber against a human lung cancer cell line (A549) was 65.50 ± 2.12 µg mL-1 and against a human breast cancer cell line (MCF7) was 19.35 ± 0.11 µg mL-1. β-D-glucan extract from the purification of boiled water extract of cultivated tuber showed cytotoxic activity at 57.78 ± 2.29 µg mL-1 against A549 and 33.50 ± 1.41 µg mL-1 against MCF7. However, the β-glucan extract from wild tuber did not show a cytotoxic effect against either the A549 or MCF7 cell lines. Also, neither of the extracts from cultivated tuber and wild tuber showed an effect against a normal cell line (MRC5). Compound profiling through by liquid chromatography mass spectrometry (LC/MS) showed the appearance of new compounds in the cultivated tuber. In conclusion, our cultivated tuber of tiger's milk mushroom using a new recipe cultivation technique showed improved nutrient and bioactive compound contents, and antioxidant and cytotoxic activities compared to the wild tuber. Further investigations are required to obtain a better quality of cultivated tuber.
Rhizopus nigricans (R. nigricans), one of the fungi that grows the fastest, is frequently discovered in postharvest fruits, it's the main pathogen of strawberry root rot. Flavonoids in Sedum aizoon L. (FSAL) is a kind of green and safe natural substance extracted from Sedum aizoon L. which has antifungal activity. In this study, the minimum inhibitory concentration (MIC) of FSAL on R. nigricans and cell apoptosis tests were studied to explore the inhibitory effect of FSAL on R. nigricans. The effects of FSAL on mitochondria of R. nigricans were investigated through the changes of mitochondrial permeability transition pore(mPTP), mitochondrial membrane potential(MMP), Ca2+ content, H2O2 content, cytochrome c (Cyt c) content, the related enzyme activity and related genes of mitochondria. The results showed that the MIC of FSAL on R. nigricans was 1.800 mg/mL, with the addition of FSAL (1.800 mg/mL), the mPTP openness of R. nigricans increased and the MMP reduced. Resulting in an increase in Ca2+ content, accumulation of H2O2 content and decrease of Cyt c content, the activity of related enzymes was inhibited and related genes were up-regulated (VDAC1, ANT) or down-regulated (SDHA, NOX2). This suggests that FSAL may achieve the inhibitory effect of fungi by damaging mitochondria, thereby realizing the postharvest freshness preservation of strawberries. This lays the foundation for the development of a new plant-derived antimicrobial agent.
We have recently been made aware by Mr. Saravanan (National University of Singapore) thatthe structure of prunin flavonoid used in their study was different to the one that we reported [...].
Dengue is a major mosquito-borne disease currently with no effective antiviral or vaccine available. Effort to find antivirals for it has focused on bioflavonoids, a plant-derived polyphenolic compounds with many potential health benefits. In the present study, antiviral activity of four types of bioflavonoid against dengue virus type -2 (DENV-2) in Vero cell was evaluated. Anti-dengue activity of these compounds was determined at different stages of DENV-2 infection and replication cycle. DENV replication was measured by Foci Forming Unit Reduction Assay (FFURA) and quantitative RT-PCR. Selectivity Index value (SI) was determined as the ratio of cytotoxic concentration 50 (CC50) to inhibitory concentration 50 (IC50) for each compound.
Epicatechin is a natural flavonoid found in green tea. It has been reported to possess an immense antioxidant effect which contributes to its therapeutic effect against a handful of ailments. In this review, we discuss its therapeutic role in the management of two of the most important human diseases; diabetes and cancer. The consumption of epicatechin has been shown to reduce blood glucose levels in diabetic patients, while is anticancer effect was attributed to its antioxidant properties, antiangiogenic and direct cytotoxicity to cancer cells. Although the exact mechanism of action of epicatechin is still being explored, there is no doubt that it is a promising candidate as an alternative. The significance of this review is to highlight the importance of the usage of natural products (in this case, epicatechin) as an alternative for the treatment of two potentially fatal diseases which is diabetes and cancer. The aim of this review is to educate the scientific community on the role of epicatechin in ameliorating the effects of diabetes and cancers on human while understanding the potential mechanisms of these aforementioned effects.
This study investigates the characteristics of an antioxidant cream made from the methanol extract of Piper sarmentosum leaves, which is locally known as the wild betel or pokok kadok in Malay. The secondary metabolites of the leaves were subjected to phytochemical tests to detect the presence of natural compounds. Antioxidant activity was described by its total phenolic content (TPC) and total flavonoid content (TFC), which was assessed by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay. A phase diagram was constructed to find a possible region to formulate an antioxidant cream. In phytochemical screening, the methanolic extract showed positive presence of alkaloids, flavonoids, steroids, terpenoids and tannins. In quantitative analysis of antioxidative components, besides having significantly higher TFC content compared with quercetin (P
A study was conducted on the chemical and biological properties of three different species of Mangifera i.e. Mangifera pajang, M. indica L., and M. kemanga leaves obtained from Pitas, Sabah. The aims of this study were to determine the presence of secondary metabolites as well as the antioxidative activities especially the catalase (CAT) and guiacol peroxidase specific activities (gPOD) in the leaves part of these three species. The extraction of these samples was carried out using three different polarities of solvents: hexane, ethyl acetate, and methanol. The total percentage of the crude extract of is 7.30% for M. pajang, 12.87% for M. indica and 7.98% for M. kemanga. Phytochemical screening was performed with various tests for each of the crude extracts. The results showed that these three species gave positive results for alkaloids, saponins, flavonoids, phenols, carbohydrates, phytosterols, and tannins metabolites. Based on the tests, CAT specific activities were significantly higher in the leaves of M. pajang with 4.35 ± 1.18 units/mg protein compared to M. indica L. and M. kemanga. The guaiacol peroxidase (gPOD) specific activities showed that M. indica L. has the highest activity with the value of 0.0047 ± 0.0004 units/mg protein.
Moringa oleifera Lam. and Centella asiatica (L.) Urb. leaves have been previously reported to exhibit antioxidant activity. The objective of the present study is to determine the in vitro antioxidant activity of the combined extracts of M. oleifera and C. asiatica (TGT-PRIMAAGE) and its effect on hydrogen peroxide (H 2O2)-induced oxidative stress in human dermal fibroblasts. TGTPRIMAAGE acted on the mechanism of hydrogen transfer as it showed scavenging activity in the DPPH assay. This is due to the presence of phenolics and flavonoids in TGT-PRIMAAGE. TGT-PRIMAAGE effectively reduced cellular generation of reactive oxygen species induced by H O2. The activities of superoxide dismutase and catalase were also increased in cells treated with TGT-PRIMAAGE. 2 Treatment with TGT-PRIMAAGE showed significant reduction (P < 0.05) in the number of senescent cells. Significant reduction (P < 0.05) of malondialdehyde was also seen in cells treated with TGT-PRIMAAGE. The p53 protein level was reduced in TGT-PRIMAAGEtreated cells, which indicates its potential in protecting the cells from oxidative stress induced by H2O2.
The acute and sub-chronic antihyperglycaemic activity, safety margin evaluations and chemical composition of ethanol extract (EE) and fractions of Gynura procumbens (GP) were studied. Streptozotocin (STZ)-induced diabetic rats (SDRs) and the Organisation for Economic Cooperation and Development (OECD) guidelines 425 and 407 were used in the antidiabetic and toxicity studies, respectively. Biochemical and haematological data obtained from both acute and sub-chronic procedures suggest that the extract is safe at the limit test dose (2000 mg/kg); thus, the oral lethal dose (LD50) exceeds 2000 mg/kg. The acceptable daily intake (ADI) was determined to be 700 mg/kg/day. In the acute antihyperglycaemic study, the n-butanol fraction (n-BF) was found to consistently lower glucose levels the most effectively, which was also demonstrated in the 14-day study. Not only did the n-BF show the highest dose-dependent glucose-lowering action (51.2% and 62.0% at 500 mg/kg and 1000 mg/kg, respectively), its effect was the closest to that of metformin (63.6%, p<0.05). The estimated amount of flavonoids in n-BF were 62.90% and 79.68% higher than the ethyl acetate fraction (EAF) and aqueous fraction (AF), respectively (p<0.05), with a corresponding value of 61.22% and 49.33% for phenolics (p<0.05). GP leaves have a no-observed-adverse-effect-level (NOAEL) and antihyperglycaemic activity corresponding to the high content of phenols and flavonoids. Therefore, GP leaves are a promising source of new antidiabetic natural products.
The terrestrial Ludisia discolor, also referred to as the jewel orchid is prized for
the quality of its leaves. L. discolor is known as a medicinal herb and is touted for its heatand
pathogen-resisting qualities. L. discolor is valuable in the production of both flavonoids
and anthocyanins, antioxidants that are exalted in the health industry. Plant cell cultures
have emerged as alternative sources of anthocyanin production. Plant protoplast cultures
are used frequently in transient gene expression studies and in the establishment of callus
and cell suspension cultures. Benefits of plant protoplast system include similarity to cells
found in plant tissues, reproduction under controlled conditions, and prevention of masking
of stress responses to previous handling techniques. A study was conducted to assess the
amenability of the stem and leaves of L. discolor to protoplast isolation. The stem and leaf
segments were weighed, sliced into thin layers, immersed in a digestion medium, washed
and then cultured onto a recovery medium. Results indicated that the production of plant
protoplasts from L. discolor may be viewed as an alternative in the generation of cell
cultures and ultimately in the production of anthocyanins from the cell cultures.
Spheroids have been shown to recapitulate the tumour in vivo with properties
such as the tumour microenvironment, concentration gradients, and tumour phenotype. As
such, it can serve as a platform for determining the growth and invasion behaviour pattern
of the cancer cells as well as be utilised for drug sensitivity assays; capable of exhibiting
results that are closer to what is observed in vivo compared to two-dimensional (2D) cell
culture assays. This study focused on establishing a three-dimensional (3D) cell culture
model using the Nasopharyngeal Carcinoma (NPC) cell line, HK1 and analysing its growth
and invasion phenotypes. The spheroids will also serve as a model to elucidate their
sensitivity to the chemotherapeutic drug, Flavopiridol. The liquid overlay method was
employed to generate the spheroids which was embedded in bovine collagen I matrix for
growth and invasion phenotypes observation. The HK1 cells formed compact spheroids
within 72 hours. Our observation from the 3 days experiments revealed that the spheroids
gradually grew and invaded into the collagen matrix, showing that the HK1 spheroids are
capable of growth and invasion. Progressing from these experiments, the HK1 spheroids
were employed to perform a drug sensitivity assay using the chemotherapeutic drug,
Flavopiridol. The drug had a dose-dependent inhibition on spheroid growth and invasion.
Clitoria ternatea is a herbaceous plant with many health benefits. Extraction is crucial to obtain its bioactive components which contribute to its antioxidant properties. Therefore, this study was conducted to find an optimum extraction condition of C. ternatea flower on total phenolic content (TPC) and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging activity) as well as to determine its total flavonoid content (TFC) and anthocyanin content based on the optimum extraction condition generated by Response Surface Methodology (RSM)-Design Expert 7.1.5. TPC, TFC and total anthocyanin of C. ternatea were conducted by Folin Ciocalteu (FC), calorimetric assay and pH differential method, respectively. The ranges of selected independent variables were ethanol concentration (30°C-90% v/v), time (60-120 min) and temperature (30°C-70°C). The optimum extraction condition was obtained at 39.62% v/v ethanol concentration, 90 min and 44.24°C. However, these values were slightly adjusted according to the convenience of equipment to operate in which ethanol concentration was adjusted to 37% v/v, time remain at 90 min and temperature at 45°C. The predicted values of TPC and DPPH radical scavenging activity were 41.60 mg GAE/g dry samples and 68.12% inhibition and were experimentally verified to be 41.17 ± 0.5 mg GAE/g dry samples and 63.53 ± 0.95% inhibition of TPC and DPPH radical scavenging activity respectively. This result has showed RSM can optimise TPC and radical scavenging activity of C. ternatea. Upon the optimum condition, the TFC determined was 187.05 ± 3.18 mg quercetin/g dried sample which was higher than TPC and the total anthocyanin content was 28.60 ± 0.04 mg/L. Hence, the extractable phenolic, flavonoid and anthocyanin compounds indicated that C. ternatea is a good source of natural antioxidant.
Conventional and modern cancer treatment were reported to manifest adverse effects to the patients. More researches were conducted to search for selective cytotoxic agent of plant natural product on cancer cells. The presences of wide range phytochemicals in Quercus infectoria (QI) extract have been implicated with the cytotoxic effect against various types of cancer cell which remain undiscovered. This present study aimed to evaluate cytotoxic effect of QI extracts on selected human cancer cells and then, the most potent extract was further analysed for general phytochemical constituents. QI galls were extracted successively with n-hexane, ethyl acetate and methanol yielded three main extracts; n-hexane (QIH), ethyl acetate (QIEA) and methanol (QIM), respectively. The most potent extract was qualitatively analysed for the present of tannin, alkaloids, glycosides, saponins, terpenoids, flavonoids and phenolic compounds. Next, the extracts were tested to determine the cytotoxic activity against cervical cancer cells (HeLa), breast cancer cells (MDA-MB-231) and liver cancer cells (Hep G2) using MTT assay. Cytotoxic activity of QI extracts against normal fibroblast (L929) cell line was also evaluated to determine the cytoselective property. Meanwhile, DMSO-treated cells served as negative control while cisplatin-treated cells served as positive control. The most potent extract then chosen to be further investigated for DNA fragmentation as hallmark of apoptosis using Hoechst staining. Qualitative phytochemical analysis revealed the presence of tannin, alkaloids, glycosides, saponins, terpenoids, flavonoids and phenolic compounds. QIEA extract exhibited the most potent cytotoxic activity against HeLa cells with (IC50 value = 6.33 ± 0.33 μg/mL) and showed cytoselective property against L929 cells. DNA fragmentation revealed QIEA induced apoptosis in the treated cells. The richness of phytochemical constituents in QIEA extract might contribute to the potency of cytotoxic activity towards HeLa cells.
Doxorubicin (DOX) adalah salah satu ubat kemoterapi yang paling berkesan untuk merawat pelbagai neoplasma seperti leukemia, limfoma dan kanser payudara. Walau bagaimanapun, ia sering dikaitkan dengan kardiomiopati. Pada masa ini, tiada rawatan yang sesuai untuk mengurangkan kesan kardiomiopati tanpa kesan sampingan yang ketara. Oleh itu, kajian ini bertujuan untuk mengkaji kesan-kesan perlindungan potensi ekstrak benih padi (RSE) terhadap kesitotoksikan yang disebabkan oleh DOX menggunakan kajian kultur sel vitro. Keupayaan antioksidan RSE dinilai, dan hasilnya menunjukkan jumlah kandungan fenolik yang lebih rendah (TPC), tetapi jumlah kandungan flavonoid total (TFC) dan kapasiti antioksidan yang setara trolox (TEAC), dibandingkan dengan ekstrak benih wheatgrass. Satu siri eksperimen spektroskopi penyerapan dan pendarfluor menunjukkan bahawa RSE boleh menghalang pembentukan kompleks DOX-DNA pada kepekatan yang diuji. Tambahan pula, daya maju sel kardiomiosit sel, H9c2 (2-1), telah diuji selepas 24, 48 dan 72 jam rawatan DOX terhadap RSE menggunakan ujian proliferasi sel berdasarkan garam tetrazolium (MTS reagent). Hasilnya menunjukkan kesan perlindungan yang signifikan terhadap RSE terhadap kesitotoksikan yang disebabkan oleh DOX. Jalur sel karsinoma nasofarinks, HK1, digunakan sebagai kawalan untuk menentukan sama ada keberkesanan DOX terjejas oleh pentadbiran bersama RSE. Hasilnya tidak menunjukkan kesan negatif terhadap keberkesanan dadah. Pelbagai sifat berfaedah RSE menunjukkan potensi kuatnya untuk membangunkan agen kardioprotektif untuk melengkapi rawatan DOX dalam tetapan klinikal.
Many medicinal plants have been used for centuries in daily life to treat microbial diseases all over the world. In this study, the in vitro antibacterial activity of aqueous and ethanol root extracts of Thespesia populnea Linn were investigated. Antimicrobial properties of T. populnea Linn was evaluated against five pathogenic bacteria and two fungi. Disc diffusion method and minimum inhibitory concentration (MIC) were determined by broth serial dilution method. The ciprofloxacin (5 μg/ml) and flucanozole (100 units/disc) were used as positive controls for bacteria and fungi respectively. Different concentrations (50, 100, 150 μg/ml) of ethanolic and aqueous root extracts of T. populnea were checked for the dose dependent antibacterial activity. Thespesia populnea showed broad spectrum antimicrobial activity against gram positive and gram negative bacteria and maximum inhibition by ethanolic extract was observed at higher dose (250 μg/ml) as 27±0.2mm. The MIC of the ethanol extract was 10 μg/ml for Staphylococcus aureus and 750 μg/ml for Candida albicans. The antifungal activity offered against S. aureus by the ethanolic extract is more than the aqueous extract. The results concluded that the anti-microbial activity of T. populnea was dose dependent. As the concentration increased the inhibition zone also increased. Flavonoids and tannins present in the extracts may be responsible for the antimicrobial activity.
Trypanosoma evansi, the causative agent of "surra", infects many species of wild and domestic animals worldwide. In the current study, the aqueous and ethanolic extracts of six medicinal plants, namely, Aquilaria malaccensis, Derris elliptica, Garcinia hombroniana, Goniothalamus umbrosus, Nigella sativa, and Strobilanthes crispus were screened in vitro for activity against T. evansi. The cytotoxic activity of the extracts was evaluated on green monkey kidney (Vero) cells using MTT-cell proliferation assay. The median inhibitory concentrations (IC50) of the extracts ranged between 2.30 and 800.97 μg/ml and the median cytotoxic concentrations (CC50) ranged between 29.10 μg/ml and 14.53 mg/ml. The aqueous extract of G. hombroniana exhibited the highest selectivity index (SI) value of 616.36, followed by A. malaccensis aqueous extract (47.38). Phytochemical screening of the G. hombroniana aqueous extract revealed the presence of flavonoids, phenols, tannins, and saponins. It is demonstrated here that the aqueous extract of G. hombroniana has potential antitrypanosomal activity with a high SI, and may be considered as a potential source for the development of new antitrypanosomal compounds.
COVID-19, caused by the SARS-CoV-2 virus, can lead to massive inflammation in the gastrointestinal tract causing severe clinical symptoms. SARS-CoV-2 infects lungs after binding its spike proteins with alveolar angiotensin-converting enzyme 2 (ACE2), and it also triggers inflammation in the gastrointestinal tract. SARS-CoV-2 invades the gastrointestinal tract by interacting with Toll-like receptor-4 (TLR4) that induces the expression of ACE2. The influx of ACE2 facilitates cellular binding of more SARS-CoV-2 and causes massive gastrointestinal inflammation leading to diarrhea. Diarrhea prior to COVID-19 infection or COVID-19-induced diarrhea reportedly ends up in a poor prognosis for the patient. Flavonoids are part of traditional remedies for gastrointestinal disorders. Preclinical studies show that flavonoids can prevent infectious diarrhea. Recent studies show flavonoids can inhibit the multiplication of SARS-CoV-2. In combination with vitamin D, flavonoids possibly activate nuclear factor erythroid-derived-2-related factor 2 that downregulates ACE2 expression in cells. We suggest that flavonoids have the potential to prevent SARS-CoV-2 induced diarrhea.
Trypanothione reductase is a key enzyme that upholds the redox balance in hemoflagellate protozoan parasites such as T. congolense. This study aims at unraveling the potency of Kolaviron against trypanothione reductase in T. congolense infection using Chrysin as standard. The experiment was performed using three different approaches; in silico, in vitro and in vivo. Kolaviron and Chrysin were docked against trypanothione reductase, revealing binding energies (-9.3 and -9.0 kcal/mol) and Ki of 0.211μM and 0.151μM at the active site of trypanothione reductase as evident from the observed strong hydrophobic/hydrogen bond interactions. Parasitized blood was used for parasite isolation and trypanothione reductase activity assay using standard protocol. Real-time PCR (qPCR) assay was implored to monitor expression of trypanothione reductase using primers targeting the 177-bp repeat satellite DNA in T. congolense with SYBR Green to monitor product accumulation. Kolaviron showed IC50 values of 2.64μg/ml with % inhibition of 66.78 compared with Chrysin with IC50 values of 1.86μg/ml and % inhibition of 53.80. In vivo studies following the administration of these compounds orally after 7 days post inoculation resulted in % inhibition of Chrysin (57.67) and Kolaviron (46.90). Equally, Kolaviron relative to Chrysin down regulated the expression trypanothione reductase gene by 1.352 as compared to 3.530 of the infected group, in clear agreement with the earlier inhibition observed at the fine type level. Overall, the findings may have unraveled the Kolaviron potency against Trypanosoma congolense infection in rats.