Apigenin C-glycosides of Microcos paniculata protects lipopolysaccharide induced apoptosis and inflammation in acute lung injury through TLR4 signaling pathway.[Pubmed: 29890216]

Acute lung injury (ALI) and its more severe form acute respiratory distress syndrome (ARDS) are life-threatening conditions with high morbility and mortality, underscoring the urgent need for novel treatments. Leaves of the medicinal herb Microcos paniculata have been traditionally used for treating upper airway infections, by virtue of its content of flavonoids such as apigenin C-glycosides (ACGs). C-glycosides have been shown to exert strong anti-inflammatory properties, although their mechanism of action remains unknown. Herein, hypothesizing that ACGs from M. paniculata inhibit progression of ALI, we used the experimental model of lipopolysaccharide (LPS)-induced ALI in BALB/c mice to evaluate the therapeutic potential of purified ACGs. Our results showed that M. paniculata ACGs inhibited lung inflammation in animals undergoing ALI. The protective effects of ACGs were assessed by determination of cytokine levels and in situ analysis of lung inflammation. ACGs reduced the pulmonary edema and microvascular permeability, demonstrating a dose-dependent down-regulation of LPS-induced TNF-α, IL-6 and IL-1β expression in lung tissue and bronchoalveolar lavage fluid, along with reduced apoptosis. Moreover, metabolic profiling of mice serum and subsequent Ingenuity Pathway Analysis suggested that ACGs activated protective protein networks and pathways involving inflammatory regulators and apoptosis-related factors, such as JNK, ERK1/2 and caspase-3/7, suggesting that ACGs-dependent effects were related to MAPKs and mitochondrial apoptosis pathways. These results were further supported by evaluation of protein expression, showing that ACGs blocked LPS-activated phosphorylation of p38, ERK1/2 and JNK on the MAPKs signaling, and significantly upregulated the expression of Bcl-2 whilst down-regulated Bax and cleaved caspase-3. Remarkably, ACGs inhibited the LPS-dependent TLR4 and TRPC6 upregulation observed during ALI. Our study shows for the first time that ACGs inhibit acute inflammation and apoptosis by suppressing activation of TLR4/TRPC6 signaling pathway in a murine model of ALI. Our findings provide new evidence for better understanding the anti-inflammatory effects of ACGs. In this regard, ACGs could be exploited in the development of novel therapeutics for ALI and ARDS.

A new piperidine alkaloid from the leaves of Microcos paniculata L.[Pubmed: 27553201]

A new piperidine alkaloid, microcosamine C (1), and one known compound, microcosamine A (2) were isolated from the leaves of Microcos paniculata. Structure elucidation was carried out using HR-ESI-MS, 1D and 2D NMR spectroscopic methods and by comparison with data reported in the literature. The absolute configuration at the C-3 hydroxy group of 1 was established by a Mosher esterification procedure. Both the isolates (1-2) were evaluated for cytotoxicity against four selected tumour cell lines and showed only weak activity against RAW 264.7 cell line.

Qualitative phytochemical screening and evaluation of anti-inflammatory, analgesic and antipyretic activities of Microcos paniculata barks and fruits.[Pubmed: 26006030]

The main objectives of this study were to qualitatively evaluate the profile of phytochemical constituents present in methanolic extract of Microcos paniculata bark (BME) and fruit (FME), as well as to evaluate their anti-inflammatory, analgesic and antipyretic activities.

α-Glucosidase inhibitory effect and simultaneous quantification of three major flavonoid glycosides in Microctis folium.[Pubmed: 23612474]

Microctis Folium, the leaves of Microcos paniculata L., is a commonly used herbal tea material. The methanol extract of Microctis Folium and its principle compounds vitexin (1), isovitexin (2) and isorhamnetin 3-O-β-D-rutinoside (3) were investigated for their α-glucosidase inhibitory effects. The extract showed strong α-glucosidase inhibitory effect (IC₅₀ = 61.30 μg/mL) and the three flavonoid glycosides 1-3 exerted satisfactory α-glucosidase inhibitory effects, with IC₅₀ values of 244.0 μM, 266.2 μM and 275.4 μM, respectively. A simple and reliable HPLC-DAD method was developed for the quantification of the three flavonoid glycosides in Microctis Folium and applied successfully to determine contents of these components in samples collected from different locations. This study suggested that Microctis Folium may be a promising candidate for development of herbal antidiabetes drugs, and vitexin, isovitexin and isorhamnetin 3-O-β-D-rutinoside can be the biomarkers and chemical markers for this plant substance.

Alkaloids from Microcos paniculata with cytotoxic and nicotinic receptor antagonistic activities.[Pubmed: 23327794]

Microcos paniculata is a large shrub or small tree that grows in several countries in South and Southeast Asia. In the present study, three new piperidine alkaloids, microgrewiapines A-C (1-3), as well as three known compounds, inclusive of microcosamine A (4), 7'-(3',4'-dihydroxyphenyl)-N-[4-methoxyphenyl)ethyl]propenamide (5), and liriodenine (6), were isolated from cytotoxic fractions of the separate chloroform-soluble extracts of the stem bark, branches, and leaves of M. paniculata. Compounds 1-6 and 1a (microgrewiapine A 3-acetate) showed a range of cytotoxicity values against the HT-29 human colon cancer cell line. When evaluated for their effects on human α3β4 or α4β2 nicotinic acetylcholine receptors (nAChRs), several of these compounds were shown to be active as nAChR antagonists. As a result of this study, microgrewiapine A (1) was found to be a selective cytotoxic agent for colon cancer cells over normal colon cells and to exhibit nicotinic receptor antagonistic activity for both the hα3β4 and hα4β2 receptor subtypes.

[Determination of organochlorine pesticide residues in Microcos paniculata by GC].[Pubmed: 23320348]

To establish a method for determination 9 organochlorine pesticide residue in Microcos paniculata by gas chromatography.

Evidence for leaf fold to remedy the deficiency of physiological photoprotection for photosystem II.[Pubmed: 22198728]

An interesting phenomenon is that some light-demanding plants fold their leaves when exposed to high light. Since high light could induce selective photodamage to photosystem II (PSII), we suggest that the leaves fold themselves to diminish the absorption of light energy and remedy the deficiency of physiological photoprotection for PSII. To test this hypothesis, we determined light responses of non-photochemical quenching (NPQ) and cyclic electron flow (CEF) and the effect of high light on PSII activity in Microcos paniculata (non-foldable species) and Bauhinia tenuiflora (foldable species). Under high light B. tenuiflora showed much lower NPQ and CEF than M. paniculata. Meanwhile, the excess light energy that cannot be harmlessly dissipated in B. tenuiflora was more compared with that in M. paniculata. After exposure to a high light of 1,900 μmol photons m(-2) s(-1) for 2 h, the maximum quantum yield of PSII, as estimated by variable to maximal fluorescence (F (v) /F (m)) decreased from 0.7 to 0.52 in the foldable species B. tenuiflora but was stable at 0.7 in the nonfoldable species M. paniculata. These results indicate that the foldable species B. tenuiflora has more sensitivity of PSII to high light stress than the nonfoldable species M. paniculata, partly as a result of less CEF and NPQ in B. tenuiflora. Our results suggest that sun leaves fold themselves under high light to remedy the deficiency of physiological photoprotection for PSII.