Antimicrobial activity of some Clerodendrum species from Egypt

Phenylethanoid Glycoside-Enriched Extract Prepared from Clerodendrum chinense Leaf Inhibits A549 Lung Cancer Cell Migration and Apoptosis Induction through Enhancing ROS Production

This study aims to investigate the antioxidant and anti-cancer activities of Clerodendrum chinense leaf ethanolic extract. The phenylethanoid glycoside-enriched extract, namely verbascoside and isoverbascoside, was determined in the ethanolic C. chinense leaf extract using the validated HPLC method. The ethanolic extract showed DPPH and ABTS free radical scavenging activities with the IC₅₀ values of 334.2 ± 45.48 μg/mL and 1012.77 ± 61.86 µg/mL, respectively, and a FRAP value of 88.73 ± 4.59 to 2480.81 ± 0.00 µM. C. chinense leaf extract exhibited anti-proliferative activity against A549 lung cancer cells in a dose- and time-dependent manner, with the IC₅₀ value of 340.63 ± 89.43, 210.60 ± 81.74, and 107.08 ± 28.90 µg/mL after treatment for 24, 48, and 72 h, respectively. The IC₅₀ values of verbascoside, isoverbascoside, and hispidulin were 248.40 ± 15.82, 393.10 ± 15.27, and 3.86 ± 0.87 µg/mL, respectively, indicating that the anti-proliferative effects of the C. chinense leaf extract mainly resulted from hispidulin and verbascoside. The selectivity index (SI) of C. chinense leaf extract against A549 lung cancer cells vs. normal keratinocytes were 2.4 and 2.8 after incubation for 24 and 48 h, respectively, suggesting the cytotoxic selectivity of the extract toward the cancer cell line. Additionally, the C. chinense leaf extract at 250 µg/mL induced late apoptotic cells up to 21.67% with enhancing reactive oxygen species (ROS) induction. Furthermore, the lung cancer cell colony formation was significantly inhibited after being treated with C. chinense leaf extract in a dose-dependent manner. The C. chinense leaf extract at 250 µg/mL has also shown to significantly inhibit cancer cell migration compared with the untreated group. The obtained results provide evidence of the anti-lung cancer potentials of the C. chinense leaf ethanolic extract.

Antiviral iridoid glycosides from Clerodendrum myricoides

The methanol root extract of Clerodendrum myricoides (Hochst.) Vatke afforded two new (1, 2) and two known (3, 4) iridoid glycosides. The structures of the isolated compounds were established based on NMR, IR, UV and MS data analyses. The crude extract and the isolated constituents were assayed for antiviral activity against the human respiratory syncytial virus (RSV) in human laryngeal epidermoid carcinoma (HEp-2) cells. The crude extract inhibited RSV infectivity at EC₅₀ = 0.21 μg/ml, while it showed cytotoxicity against HEp-2 cells with CC₅₀ = 9 μg/ml. Compound 2 showed 43.2% virus inhibition at 100 μM, while compounds 1 as well as 3 and 4 had only weak antiviral and cytotoxic activities.

Phytomedicine from Middle Eastern Countries: An Alternative Remedy to Modern Medicine against Candida spp Infection

Candida spp are capable of infecting both normal and immunocompromised individuals. More recently, Candida infections have spread considerably in healthcare settings, especially in intensive care units, where it is the most frequently encountered pathogen. Candida albicans is the commonest species encountered, although infections by non-albicans species have also risen in the past few years. The pathogenicity of Candida is credited to its aptitude to change between yeast and hyphal modes of growth. Candida spp produce biofilms on synthetic materials that protect them and facilitate drug resistance and act as a source for chronic and recurrent infections. Primarily, azoles antifungal agents are utilized to treat Candida infection that targets the ergosterol synthesis pathway in the cell wall. The development of antifungal resistance in Candida species is a major reason for treatment failure, and hence, there is a need to develop newer antifungal molecules and/or modifications of existing antifungals to make them more effective and less toxic. This has led researchers to oversee the plants to discover newer antimicrobials. Middle Eastern countries are well known for their landscape ranging from dry and sandy deserts to snow-capped mountains. However, they comprise enormous plant diversity with over 20,000 different species showing various types of bioactivities, such as anticancer, antidiabetic, and antimicrobial activities. Especially, the antifungal potential of these phytoproducts could be exploited in the clinical setting for therapy. The present review examines some of the promising alternative natural compounds that have been tested and found effective in treating Candida infections in vitro in some Middle Eastern countries.

Cytotoxic activity of the chemical constituents of Clerodendrum indicum and Clerodendrum villosum roots

OBJECTIVE

The roots of two Thai medicinal plants, Clerodendrum indicum and Clerodendrum villosum are found in traditional medicine practices. The aim of this research was to preliminarily study the cytotoxicity of extracts of their roots, and the parts that possessed cytotoxic activity were separated on a chromatograph to identify their active compounds.

METHODS

The extracts of both plants were screened for cytotoxicity on the SW620 cell line and the compounds isolated from the active extracts were further evaluated for their cytotoxic activity against five human cancer cell lines, including SW620, ChaGo-K-1, HepG2, KATO-III and BT-474 using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay.

RESULTS

Dichloromethane extracts of C. indicum and C. villosum were active against the SW620 cell line. Triterpenoids were mostly obtained from the extracts of these plants (0.28% and 1.02%, respectively) and exhibited varying degrees of cytotoxicity and specificity against the tested cell lines. Two triterpenoids, oleanolic acid 3-acetate and betulinic acid, displayed moderate to strong cytotoxicity toward all cancer cell lines, with 50% inhibitory concentration (IC₅₀) values of 1.66-20.49 µmol/L, whereas 3β-hydroxy-D:B-friedo-olean-5-ene and taraxerol were cytotoxic to only the SW620 cell line (IC₅₀ = 23.39 and 2.09 µmol/L, respectively). Triterpenoid, lupeol, showed potent cytotoxicity on both SW620 (IC₅₀ = 1.99 µmol/L) and KATO-III cell lines (IC₅₀ = 1.95 µmol/L), while a flavonoid, pectolinarigenin, displayed moderate cytotoxicity against these cells (IC₅₀ = 13.05 and 24.31 µmol/L, respectively). Although the widely distributed steroid, stigmasterol, was effective against the SW620 cell line (IC₅₀ = 2.79 µmol/L) and β-sitosterol was also active against SW620 (IC₅₀ = 11.26 µmol/L), BT-474 (IC₅₀ = 14.11 µmol/L) and HepG2 cancer cells (IC₅₀ = 20.47 µmol/L), none of the characteristic 24β-ethylsteroids of either Clerodendrum species were shown to be cytotoxic.

CONCLUSION

This study is the first report on the presence of cytotoxic triterpenoids from the roots of these medicinal plants, which have been used in herbal formulas as an antipyretic. Our findings support further in-depth study of this pharmacological activity as an anticancer agent.

Formiside and seco-formiside: lignin glycosides from leaves of Clerodendrum formicarum Gürke (Lamiaceae) from Cameroon

The ethanol soluble part of the leaves of Clerodendrum formicarum, a Lameacious plant of Cameroon, afforded two new lignin glycosides named formiside and seco-formiside. Structures of both the isolated constituents have been elucidated with the aid of 1D and 2D NMR spectroscopic techniques.

Immunomodulatory activity of polysaccharides isolated from Clerodendrum splendens: beneficial effects in experimental autoimmune encephalomyelitis

BACKGROUND

Extracts of leaves from Clerodendrum have been used for centuries to treat a variety of medicinal problems in tropical Africa. However, little is known about the high-molecular weight active components conferring therapeutic properties to these extracts.

METHODS

Polysaccharides from the leaves of Clerodendrum splendens were extracted and fractionated by ion exchange and size-exclusion chromatography. Molecular weight determination, sugar analysis, degree of methyl esterification, and other chemical characterization of the fractions were performed. Immunomodulatory activity of the fractions was evaluated by determining their ability to induce monocyte/macrophage nitric oxide (NO), cytokine production, and mitogen-activated protein kinase (MAPK) phosphorylation. Experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6 mice, and severity of EAE was monitored in mice treated with intraperitoneal (i.p.) injections of the most active polysaccharide fraction. Lymph nodes (LN) and spleen were harvested, and levels of cytokines in supernatants from LN cells and splenocytes challenged with myelin oligodendrocyte glycoprotein peptide were determined.

RESULTS

Fractions containing type II arabinogalactan had potent immunomodulatory activity. Specifically, the high-molecular weight sub-fraction CSP-AU1 (average of 38.5 kDa) induced NO and cytokine [interleukin (IL)-1α, -1β, -6, -10, tumor necrosis factor (TNF; designated previously as TNF-α), and granulocyte macrophage-colony stimulating factor (GM-CSF)] production by human peripheral blood mononuclear cells (PBMCs) and monocyte/macrophages. CSP-AU1-induced secretion of TNF was prevented by Toll-like receptor 4 (TLR4) antagonist LPS-RS, indicating a role for TLR4 signaling. Treatment with CSP-AU1 also induced phosphorylation of a number of MAPKs in human PBMC and activated AP-1/NF-κB. In vivo treatment of mice with CSP-AU1 and CSP-NU1 resulted in increased serum IL-6, IL-10, TNF, monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1α/CCL3, and MIP-1β/CCL4. CSP-AU1 treatment of mice with EAE (50 mg/kg, i.p., daily, 13 days) resulted in significantly reduced disease severity in this experimental model of multiple sclerosis. Levels of IL-13, TNF, interferon (IFN)-γ, IL-17, and GM-CSF were also significantly decreased, whereas transforming growth factor (TGF)-β was increased in LN cells from CSP-AU1-treated EAE mice.

CONCLUSIONS

Polysaccharide CSP-AU1 is a potent natural innate immunomodulator with a broad spectrum of agonist activity in vitro and immunosupressive properties after chronic administration in vivo.