In Vitro Anti-Diabetic Activities and UHPLC-ESI-MS/MS Profile of Muntingia calabura Leaves Extract

Anti-diabetic compounds from natural sources are now being preferred to prevent or treat diabetes due to adverse effects of synthetic drugs. The decoction of Muntingia calabura leaves was traditionally consumed for diabetes treatment. However, there has not been any published data currently available on the processing effects on this plant’s biological activity and phytochemical profile. Therefore, this study aims to evaluate the effect of three drying methods (freeze-drying (FD), air-drying (AD), and oven-drying (OD)) and ethanol:water ratios (0, 50, and 100%) on in vitro anti-diabetic activities of M. calabura leaves. In addition, an ultrahigh-performance-liquid chromatography–electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) method was used to characterize the metabolites in the active extract. The FD M. calabura leaves, extracted with 50% ethanol, is the most active extract that exhibits a high α-glucosidase and α-amylase inhibitory activities with IC₅₀ values of 0.46 ± 0.05 and 26.39 ± 3.93 µg/mL, respectively. Sixty-one compounds were tentatively identified by using UHPLC-ESI-MS/MS from the most active extract. Quantitative analysis, by using UHPLC, revealed that geniposide, daidzein, quercitrin, 6-hydroxyflavanone, kaempferol, and formononetin were predominant compounds identified from the active extract. The results have laid down preliminary steps toward developing M. calabura leaves extract as a potential source of bioactive compounds for diabetic treatment.

Fractionated Extracts From Gnidia kraussiana (Malvales: Thymeleaceae) as Bioactive Phytochemicals for Effective Management of Callosobruchus maculatus (Coleoptera: Chrysomelidae) in Stored Vigna unguiculata (Fabales: Fabaceae) Seeds

One of the most important global problems is protecting food from insect pests. The negative effects of synthetic insecticides on human health led to a resurgence of interest in botanical insecticides due to their minimal ecological side effects. Therefore, the insecticidal potential of hexane, acetone, and methanol extracts of Gnidia kraussiana Meisn roots at 1 and 5g/kg, and neem seed oil (NSO), used as standard insecticide, were evaluated. Ovicidal and larvicidal toxicity was tested by treating freshly laid eggs and larvae at different immature stages of Callosobruchus maculatus (F.). Cowpea (Vigna unguiculata) (L.) Walp seed damage and weight loss were assessed after a storage period of 4 mo. Repellency effects were detected in choice test using a linear olfactometer. All the fractions were toxic to C. maculatus; however, their bioactivities were inversely correlated with products polarity. Extracts proved to be more toxic than the commercial NSO. The acetone extract was more effective against immature stages of C. maculatus than the methanol extract; eggs, first-, and second-instar larvae being the more susceptible. No cowpea seed damage and weight loss were recorded from the seeds treated with hexane and acetone extracts at the dosage of 5 g/kg, after 4 mo of storage. Extracts evoked stronger repellency effects compared with the tested standard insecticide. According to the above, hexane and acetone extracts are good candidates for incorporation in integrated pest management programs for the control of C. maculatus in stored cowpea seeds.

Phenolic Constituents of the Roots of Rhamnoneuron balansae with Senolytic Activity

With the advent of senolytic agents capable of selectively removing senescent cells in old tissues, the perception of age-associated diseases has been changing from being an inevitable to a preventable phenomenon of human life. In the search for materials with senolytic activity from natural products, six new flavonostilbenes (1-6), three new phenylethylchromanones (7-9), three new phenylethylchromones (10-12), and four known compounds (13-16) were isolated from the roots of Rhamnoneuron balansae. The chemical structures of these isolated compounds were determined based on the interpretation of spectroscopic data, including 1D and 2D NMR, ECD, and HRMS. The absolute configuration of compound 1 was also determined by a Mosher ester analysis and ECD calculations. Compounds 6-8 were shown to selectively destroy senescent cells, and the promoter activity of p16INK4A, a representative senescence marker, was reduced significantly by compound 6. The present results suggest the potential activity of flavonostilbene and phenylethylchromanone skeletons from R. balansae as new senolytics.

Safety evaluation of orally-administered methanol extract of Muntingia calabura Linn. leaves: A sub-chronic toxicity study in Sprague Dawley rats

Muntingia calabura (M. calabura), locally known as "kerukup siam" or "buah ceri" belongs to the family Muntingiaceae and has been scientifically demonstrated to exert various pharmacological activities. The objectives of the current study are to evaluate the antioxidant activities and to determine the subchronic toxicity of 90 days orally-administered methanol extract of M. calabura (MEMC) in male Sprague Dawley rats. The rats were randomly divided into four groups (n=6). Vehicle control received 8% tween 80 and treatment group received 50, 250 and 500 mg/kg of MEMC orally administered daily for 90 days. Blood collection was carried out to obtain the hematological and biochemical profile of the rats. The organs harvested were subjected to histopathological analysis. For the antioxidant test, the extract was subjected to antioxidant study using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH)- and superoxide anion-radical scavenging activity, total phenolic content (TPC) and phytochemical screening. Results obtained show that no adverse effects were observed during the experimental period. Hematological and biochemical analysis also showed no significant changes in this toxicity study. Besides, antioxidant analyses revealed that MEMC has higher DPPH- and SOD-radical scavenges activity as well as higher TPC value. In conclusion, M. calabura is safe for consumption and possesses beneficial antioxidant effect.

Methanol extract of Muntingia calabura leaves attenuates CCl4-induced liver injury: possible synergistic action of flavonoids and volatile bioactive compounds on endogenous defence system

CONTEXT

Muntingia calabura L. (Muntingiaceae) exerts antioxidant and anti-inflammatory activities, thus, it might be a good hepatoprotective agent.

OBJECTIVE

This study investigates the effect of methanol extract of M. calabura leaves (MMCL) on hepatic antioxidant and anti-inflammatory activities in CCl₄-induced hepatotoxic rat.

MATERIALS AND METHODS

Sprague Dawley rats (n = 6) were treated (p.o.) with 10% DMSO (Groups 1 and 2), 50 mg/kg N-acetylcysteine (Group 3) or, 50, 250, or 500 mg/kg MMCL (Groups 4-6) for 7 consecutive days followed by pretreatment (i.p.) with vehicle (Group 1) or 50% CCl₄ in olive oil (v/v) (Groups 2-6) on day 7th. Plasma liver enzymes and hepatic antioxidant enzymes and pro-inflammatory cytokines concentrations were measured while liver histopathology was examined.

RESULTS

MMCL, at 500 mg/kg, significantly (p < 0.05) ameliorated CCl₄-induced hepatotoxicity by decreasing the plasma level of alanine transaminase (429.1 versus 168.7 U/L) and aspartate transaminase (513.8 versus 438.1 U/L) as well as the tissue level of nitric oxide (62.7 versus 24.1 nmol/g tissue). At 50, 250, or 500 mg/kg, MMCL significantly (p < 0.05) reduced the tumour necrosis factor α (87.8 versus 32.7 pg/mg tissue), interleukin-1β (1474.4 versus 618.3 pg/mg tissue), and interleukin-6 (136.7 versus 30.8 pg/mg tissue) while increased the liver catalase (92.1 versus 114.4 U/g tissue) and superoxide dismutase (3.4 versus 5.5 U/g tissue). Additionally, qualitative phytochemicals analysis showed that MMCL contained gallic acid, ferulic acid, quercetin, and genistein.

DISCUSSION AND CONCLUSIONS

MMCL ability to attenuate CCl₄-induced hepatotoxicity could be helpful in the development of hepatoprotective agents with fewer side effects.

Stellera chamaejasme and Its Main Compound Luteolin 7-O-Glucoside Alleviates Skin Lesions in Oxazolone- and 2,4-Dinitrochlorobenzene-Stimulated Murine Models of Atopic Dermatitis

Stellera chamaejasme, also known as "Langdu", has been traditionally used for the management of skin-related diseases such as psoriasis and skin ulcers. The aim of this study was to determine whether S. chamaejasme and its major component, luteolin 7-O-glucoside, have a preventive effect on the development of atopic dermatitis in oxazolone-treated BALB/c mice and 2,4-dinitrochlorobenzene-treated hairless mice. The epicutaneous applications of oxazolone and 2,4-dinitrochlorobenzene evoke an experimental murine atopic dermatitis-like reaction in BALB/c mouse ears and SKH-1 hairless mice. Atopic skin symptoms, including erythema (redness), pruritus (itching), exudation (weeping), excoriation (peeling), and lichenification (skin thickening), responded to treatment with S. chamaejasme aerial parts EtOH extract for 2 or 3 weeks. Histopathological examination revealed S. chamaejasme aerial parts EtOH extract significantly reduced inflammatory cell infiltration when applied to atopic dermatitis mice. In addition, luteolin 7-O-glucoside, the major active compound of the S. chamaejasme aerial parts EtOH extract, decreased serum IgE and IL-4 levels and transepidermal water loss and increased skin hydration, therefore exhibiting strong anti-atopic dermatitis activity in 2,4-dinitrochlorobenzene-induced atopic dermatitis mice. In this study, we confirmed antipruritic and antidermatitic effects of S. chamaejasme extract and its main component luteolin 7-O-glucoside in atopic dermatitis murine models. The study shows S. chamaejasme aerial parts EtOH extract and luteolin 7-O-glucoside are most likely to be potential drug candidates for atopic dermatitis treatment.