Melaleuca rugulosa (Link) Craven Tannins: Appraisal of anti-inflammatory, radical scavenging activities, and molecular modeling studies.

ETHNOPHARMACOLOGICAL RELEVANCE: Genus Melaleuca or tea tree species are well known to be an important source of biological active oils and extracts. The biological significance appears in their usage for treatment of several clinical disorder owing to their traditional uses as anti-inflammatory, antibacterial, antifungal, and cytotoxic activities. AIM OF THE STUDY: Our study aimed to investigate the metabolic profile of the M. rugulosa polyphenol-rich fraction along with determination of its anti-inflammatory potential, free radical scavenging and antiaging activities supported with virtual understanding of the mode of action using molecular modeling strategy. MATERIALS AND METHODS: The anti-inflammatory activity of the phenolic rich fraction was investigated through measuring its inhibitory activity against inflammatory mediators viz tumor necrosing factor receptor-2 (TNF-α) and cyclooxygenases 1/2 (COX-1/2) in a cell free and cell-based assays. Moreover, the radical scavenging activity was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC) and ß-carotene assays, while the antiaging activity in anti-elastase, anti-collagenase, and anti-tyrosinase inhibitory assays. Finally, the biological findings were supported with molecular docking study using MOE software. RESULTS: The chromatographic purification of the polyphenol-rich fraction of Melaleuca rugulosa (Link) Craven afforded fourteen phytoconstituents (1-14). The anti-inflammatory gauging experiments demonstrated inhibition of inflammatory-linked enzymes COX-1/2 and the TNF-α at low µg/mL levels in the enzyme-based assays. Further investigation of the underlying mechanism was inferred from the quantification of protein levels and gene expression in the lipopolysaccharide (LPS)-activated murine macrophages (RAW264.7) in vitro model. The results revealed the reduction of protein synthesis of COX-1/2 and TNF-α with the down regulation of gene expression. The cell free in vitro radical scavenging assessment of the polyphenol-rich fraction revealed a significant DPPH reduction, peroxyl radicals scavenging, and ß-carotene peroxidation inhibition. Besides, the polyphenol-rich fraction showed a considerable inhibition of the skin aging-related enzymes as elastase, collagenase, and tyrosinase. Ultimately, the computational molecular modelling studies uncovered the potential binding poses and relevant molecular interactions of the identified polyphenols with their targeted enzymes. Particularly, terflavin C (8) which showed a favorable binding pose at the elastase binding pocket, while rosmarinic acid (14) demonstrated the best binding pose at the COX-2 catalytic domain. In short, natural polyphenols are potential candidates for the management of free radicals, inflammation, and skin aging related conditions. CONCLUSION: Natural polyphenols are potential candidates for the management of free radicals, inflammation, and skin aging related conditions.

Ethnopharmacological impact of Melaleuca rugulosa (Link) Craven leaves extract on liver inflammation.

ETHNOPHARMACOLOGICAL RELEVANCE: Melaleuca species have been used by many ethnic communities for the management and treatment of several ailments as hemorrhoids, cough, skin infections, rheumatism, sore throat, pain, inflammation, and digestive system malfunctions. However, the detailed mechanistic pharmacological effect of Melaleuca rugulosa (Link) Craven leaves in the management of liver inflammation has not been yet addressed. AIM OF THE STUDY: The present study aimed to evaluate the anti-inflammatory, antioxidant, and antiapoptotic capacities of the aqueous methanol extract of M. rugulosa leaves in relevance to their flavonoid content using an appropriate in vivo model. MATERIALS AND METHODS: The aqueous methanol extract of M. rugulosa leaves was administered to the rats at three non-toxic doses (250, 500, and 1000 mg/kg) for seven days prior to the initiation of liver-injury induced by paracetamol (3 g/kg). Liver enzymes including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were evaluated in serum samples. The oxidative stress markers including reduced glutathione (GSH), malondialdehyde (MDA), and nitric oxide (NO) levels as well as the inflammatory markers such as tumour necrosis factor-alpha (TNF-α) and nuclear factor-kappa B (NF-κB), were assessed in liver homogenate. The results were supported by histopathological and immuno-histochemical studies. The phytochemical investigation of the flavonoid-rich fraction of the aqueous methanol extract was accomplished using different chromatographic and spectroscopic techniques. RESULTS: The aqueous methanol extract of M. rugulosa leaves showed a powerful hepatoprotective activity evidenced by the significant reduction of MDA and NO levels, as well as increasing GSH and catalase activity. Moreover, the extract exhibited anti-inflammatory and antiapoptotic activities witnessed by decreasing TNF-α, NF-κB, iNOS, p-JNK, caspase-3, BAX, and increasing Bcl-2 levels. Moreover, the pretreatment of rats with all doses of M. rugulosa leaves extract showed a significant decrease in liver weight/body weight (LW/BW) ratio, and total bilirubin induced by paracetamol. On the other hand, the chromatographic separation of the flavonoid-rich fraction afforded twenty known flavonoids namely; iso-orientin (1), orientin (2), isovitexin (3), vitexin (4), quercetin-3-O-ß-D-glucuronid methyl ether (5), quercetin-3-O-ß-D-mannuronpyranoside (6), isoquercetin (7), quercitrin (8), kaempferol-3-O-ß-D-mannuronopyranoside (9), kaempferol-7-O-methyl ether-3-O-ß-D-glucopyranoside (10), guaijaverin (11), avicularin (12), kaempferide-3-O-ß-D-glucopyranoside (13), astragalin (14), afzelin (15), luteolin (16), apigenin (17), quercetin (18), kaempferol (19), and catechin (20). CONCLUSION: The aqueous methanol extract of M. rugulosa leaves showed potential hepatoprotective, antioxidant, and anti-inflammatory activities against paracetamol-induced liver inflammation which is correlated at least in part to its considerable phenolic content.

Growth Inhibition and Apoptotic Effect of Pine Extract and Abietic Acid on MCF-7 Breast Cancer Cells via Alteration of Multiple Gene Expressions Using In Vitro Approach.

In vitro anti-proliferative activity of Pinus palustris extract and its purified abietic acid was assessed against different human cancer cell lines (HepG-2, MCF-7 and HCT-116) compared to normal WI-38 cell line. Abietic acid showed more promising IC50 values against MCF-7 cells than pine extract (0.06 µg/mL and 0.11 µM, respectively), with insignificant cytotoxicity toward normal fibroblast WI-38 cells. Abietic acid triggered both G2/M cell arrest and subG0-G1 subpopulation in MCF-7, compared to SubG0-G1 subpopulation arrest only for the extract. It also induced overexpression of key apoptotic genes (Fas, FasL, Casp3, Casp8, Cyt-C and Bax) and downregulation of both proliferation (VEGF, IGFR1, TGF-ß) and oncogenic (C-myc and NF-κB) genes. Additionally, abietic acid induced overexpression of cytochrome-C protein. Furthermore, it increased levels of total antioxidants to diminish carcinogenesis and chemotherapy resistance. P. palustris is a valuable source of active abietic acid, an antiproliferative agent to MCF-7 cells through induction of apoptosis with promising future anticancer agency in breast cancer therapy.

Polyphenolic profile and ethno pharmacological activities of Callistemonsubulatus (Cheel) Craven leaves cultivated in Egypt.

ETHNOPHARMACOLOGICAL RELEVANCE: The genus Callistemon (syn. Melaleuca) of the myrtle family (Myrtaceae) has been documented as an integral part in the ethnobotanical system of the indigenous people of Australian mainland and many of its islands. Several Callistemons including the species subulatus were used by aboriginal Australians for making rafts, roofs for shelters, bandages, and food recipes, in addition to the management of wounds, infections, pain, cough, bronchitis, and gastrointestinal tract (GIT) disorders. AIM OF THE STUDY: The current study is designed to document the therapeutic effect of the aqueous methanolic extract (AME) of C. sabulatus Chell (syn. M. sabulata) leaves in the management of diarrhea and pain. Also, its influence on additional pharmacological modalities that are related to oxidative stress just as skin aging. Ultimately, the polyphenolic profile of the extract is disclosed and correlated to the aforementioned bioactivities. MATERIALS AND METHODS: The extract was fractionated using various chromatography techniques and the structures of the isolated compounds were determined based on their chemical and spectral data. The antioxidant activity was assessed using multiple models, including 2,2-diphenyl-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC) and ß-carotene bleaching assays. The anti-skin aging effect was evaluated using different relevant enzymatic assays. The antinociceptive activity was investigated using acetic acid-induced writhing, hot plate test, and formalin-induced paw licking in mice models. The antidiarrheal activity was gauge using the castor oil induced diarrhea, enter pooling and gastrointestinal motility in vivo models. RESULTS: Diverse polyphenols, including quercetin-3-O-ß-D-glucuronopyranoside (1), kaempferol-3-O-ß-D-glucuronopyranoside (2), strictinin (3), quercetin-3-O-(2``-O-galloyl)-ß-D-glucuronopyranoside (4), afzelin (5), di-galloyl glucose (6), mono-galloyl glucose (7), acacetin (8), apigenin-6,7-dimethyl ether (9), kaempferol trimethyl ether (10), dimethoxy chrysin (11), quercetin (12), kaempferol (13), methyl gallate (14), and gallic acid (15) were identified. The extract exhibited as significant antioxidant activity even better than that of Trolox or BHT. Moreover, it exerts elastase, tyrosinase, and collagenase inhibition activities, in addition to the significant peripheral and central analgesic activity in a dose-dependent manner (P < 0.0001). In castor oil induced diarrhea model, AME significantly prolonged the diarrhea onset, decreased the frequency of defecation, and weight of feces. Likewise, it exhibited a significant reduction in the gastrointestinal motility in charcoal meal model (P < 0.0001) and a considerable inhibitory effect on gastrointestinal transit and peristaltic index with all investigated doses (P < 0.0001). CONCLUSION: Ethnobotanicals are versatile resources for the management of various ailments by indigenous people and the experimental research is utmost to validate and uncover their pharmacological relevance. C. sabulatus leaves have strong antioxidant, analgesic, anti-skin aging, and antidiarrheal activities which are validated for the first time by various in vitro and in vivo models. The metabolic profile of the unprecedented AME of C. sabulatus leaves compromises a wide array of bioactive polyphenolic metabolites including, flavonoids, tannins, and phenolic acids that are correlated to the observed bioactivities. Altogether, ethnobotanicals with high and diverse contents of polyphenols are potential candidates for the management of various human aliments including neuropathies, GIT disorders, and skin aging conditions.

131 -Oxophorbine protopheophorbide A from Ziziphus lotus as a novel mesenchymal-epithelial transition factor receptor inhibitory lead for the control of breast tumor growth in vitro and in vivo.

The failure of chemotherapy especially in triple negative breast cancer (TNBC) patients has been correlated with the overexpression of the mesenchymal-epithelial transition factor (c-Met) receptor. Thus, the hepatocyte growth factor (HGF)/c-Met signaling axis has gained considerable attention as a valid molecular target for breast cancer therapy. This study reports for the first time the discovery of the 131 -oxophorbines pheophorbide A and protopheophorbide A along with chlorophyllide A from Ziziphus lotus, an edible typical Tunisian plant, as the potent antiproliferative compounds against the human breast cancer cells MDA-MB-231 and MCF-7. Compared to other compounds, protopheophorbide A exerted the highest light-independent antiproliferative effect against the metastatic TNBC MDA-MB-231 cells (IC50 = 6.5 µM). In silico, this compound targeted the kinase domain of multiple c-Met crystal structures. It potently inhibited the kinase domain phosphorylation of wild and mutant c-Met in Z-LYTE kinase assay. Protopheophorbide A inhibited HGF-induced downstream c-Met-dependent cell proliferation, survival, adhesion and migration through RAF/MEK/ERK and PI3K/PTEN/AKT signaling pathways modulation, ROS generation and activation of JNK and p38 pathways. Interestingly, this compound impaired the ability of the MDA-MB-231 cells to adhere at different extracellular matrix proteins by reducing the HGF-induced expression of integrins αv, ß3, α2, and ß1. Moreover, protopheophorbide A exhibited anti-migratory properties (IC50 = 2.2 µM) through impacting the expression levels of E-cadherin, vimentin, ß-catenin, FAK, Brk, Rac, and Src proteins. Importantly, treatment with protopheophorbide A significantly inhibited the MDA-MB-231 tumor growth in vivo. Our results suggest that protopheophorbide A could be a novel c-Met inhibitory lead with promise to control c-Met/HGF-dependent breast malignancies.

Rutin as A Novel c-Met Inhibitory Lead for The Control of Triple Negative Breast Malignancies.

Triple negative breast cancer (TNBC) has high metastatic and mortality potential and lacks effective and selective therapeutic options. Aberrant dysregulation of the receptor tyrosine kinase c-Met promotes TNBC progression, motility and survival and therefore considered a valid therapeutic target. Among various identified anticancer agents, plant polyphenols (PPs) including flavonoids, have been shown to be safe and proven for their antitumor activity through modulating diverse macromolecular targets. This study reports the bioassay-guided identification of the common flavonol glycoside rutin as breast cancer cell proliferation, migration and invasion inhibitor. The cell free Z'-LYTE kinase assay, Western blot and in silico docking experiments uncovered, for the first time, c-Met kinase as a potential mechanistic target for rutin-mediated anticancer effects on TNBC cell lines. Likewise, the intraperitoneal injection of rutin at 30 mg/kg, 3X/week, significantly reduced the growth of the TNBC MDA-MB-231/GFP orthotopic xenograft in nude mouse model. These results clearly designate the functional dietary flavonoid rutin as a potential lead for the prevention and control of c-Met-dependent breast malignancies.

Norstictic Acid Inhibits Breast Cancer Cell Proliferation, Migration, Invasion, and In Vivo Invasive Growth Through Targeting C-Met.

Breast cancer is a major health problem affecting the female population worldwide. The triple-negative breast cancers (TNBCs) are characterized by malignant phenotypes, worse patient outcomes, poorest prognosis, and highest mortality rates. The proto-oncogenic receptor tyrosine kinase c-Met is usually dysregulated in TNBCs, contributing to their oncogenesis, tumor progression, and aggressive cellular invasiveness that is strongly linked to tumor metastasis. Therefore, c-Met is proposed as a promising candidate target for the control of TNBCs. Lichens-derived metabolites are characterized by their structural diversity, complexity, and novelty. The chemical space of lichen-derived metabolites has been extensively investigated, albeit their biological space is still not fully explored. The anticancer-guided fractionation of Usnea strigosa (Ach.) lichen extract led to the identification of the depsidone-derived norstictic acid as a novel bioactive hit against breast cancer cell lines. Norstictic acid significantly suppressed the TNBC MDA-MB-231 cell proliferation, migration, and invasion, with minimal toxicity to non-tumorigenic MCF-10A mammary epithelial cells. Molecular modeling, Z'-LYTE biochemical kinase assay and Western blot analysis identified c-Met as a potential macromolecular target. Norstictic acid treatment significantly suppressed MDA-MB-231/GFP tumor growth of a breast cancer xenograft model in athymic nude mice. Lichen-derived natural products are promising resources to discover novel c-Met inhibitors useful to control TNBCs.