HIV-1 integrase inhibitory phenylpropanoid glycosides from Clerodendron trichotomum

Green Synthesis of Aluminum Oxide Nanoparticles Using Clerodendrum phlomidis and Their Antibacterial, Anti-inflammatory, and Antioxidant Activities

INTRODUCTION

 Clerodendrum phlomidis plays a significant role in many indigenous medical systems, and it can be mostly found in Southeast Asia. The objective of the study was to synthesize and characterize the biosynthesized aluminum oxide nanoparticles (AlO-NPs) using C. phlomidis and analyze their antibacterial (bactericidal), antioxidant, and anti-inflammatory activities.

METHODS

The extract was prepared by the autoclave-assisted method, and the AlO-NPs were synthesized by the green synthesis method. The biosynthesized AlO-NPs were characterized by ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FT-IR), field emission scanning electron microscopy (FE-SEM), and energy dispersive X-ray (EDX) analysis. The antibacterial property was assessed by the Kirby-Bauer well diffusion method, and the antioxidant activity was checked by DPPH (2,2-diphenyl-1-picrylhydrazyl) activity compared with the control L-ascorbic acid. Anti-inflammatory activity was evaluated by an albumin denaturation assay, and diclofenac was used as a control. IBM SPSS Statistics for Windows, Version 21.0 was used for the statistical analysis.  Results: An absorption peak at a wavelength of 380 nm was detected by UV-Vis spectroscopy analysis. It proves that AlO-NPs have been successfully produced by the green synthesis method. The results of the FT-IR study demonstrated the existence of numerous chemicals and functional groups in the 500-3500 cm-1 range. AlO-NPs from the plant extract were subjected to FE-SEM analysis, which revealed an aggregated or spherically cluster-like structure. The sample's elemental makeup, which revealed that it included 38% aluminum and 28% oxygen, was identified with the help of the EDX, and this verified the high purity of the AlO-NPs. The results of the antibacterial activity of AlO-NPs revealed that there was a zone of inhibition for Enterococcus faecalis; however, there was no zone of inhibition for Streptococcus mutans. The synthesized AlO-NPs exhibit strong antioxidative (DPPH activity) and anti-inflammatory (albumin denaturation assay) action. In this work, the in vitro antioxidant activity of C. phlomidis was assessed using the standard, L-ascorbic acid, as a measure of DPPH activity. At a maximum concentration of 500 µg/ml, the obtained results showed the incredible antioxidant properties of the investigated AlO-NPs synthesized from the plant extracts and demonstrated 90% inhibition. AlO-NPs that were biosynthesized showed effective anti-inflammatory activity at a higher concentration of 100 µg/ml and demonstrated 89% inhibition in contrast to the drug diclofenac sodium.

CONCLUSION

According to the study's findings, AlO-NPs made using a greener synthesis approach have the potential to be used in a variety of industries and are also an affordable and sustainable way to effectively act as anti-inflammatory and antioxidant agents.

Bioassay Analysis and Molecular Docking Study Revealed the Potential Medicinal Activities of Active Compounds Polygonumins B, C and D from Polygonum minus (Persicaria minor)

Polygonumins B, C and D, derivative compounds of polygonumins A, were isolated from the stem of Polygonum minus. Based on NMR results, the structure of polygonumins derivatives is comprised of four phenylpropanoid units and a sucrose unit, with a similar structure to polygonumins A. However, the structural differences between polygonumins B (1), C (2) and D (3) can be distinguished based on the existence of methoxy, ethanoyl and hydroxyl groups and protons which bind to C-4, C-4′ and C-3″. Interestingly, these bioactive compounds showed various medicinal properties based on our investigation on antioxidant, anticholinesterase and anti-HIV-1 protease activities. The IC50 value of DPPH and ABTS (antioxidant activities) was in the following descending order: polygonumins B > polygonumins C > polygonumins A > polygonumins D. In addition, almost similar pattern of antioxidant activity was observed for anti-acetylcholinesterase activity based on its IC50 value in descending order: polygonumins B > polygonumins C > polygonumins D > polygonumins A. On the other hand, polygonumins C and D showed inhibition of HIV-1 protease activity more than the positive control, pepstatin A. Finally, molecular docking studies on AChE and BChE proteins were carried out in order to gain insight into the mode of interactions between these compounds and the active residues for both enzymes. These remarkable findings indicate that these compounds have potential to be developed as targeted drugs for Alzheimer’s disease or as anti-HIV drugs.

Leucosceptosides A and B: Two Phenyl-Ethanoid Glycosides with Important Occurrence and Biological Activities

In this review paper, the occurrence in the plant kingdom, the chemophenetic value and the biological activities associated with two specific phenyl-ethanoid glycosides, i.e., leucosceptoside A and leucosceptoside B, were reported. This is the first work ever conducted on such a subject. Analysis of the literature data clearly led to three important conclusions: leucosceptoside A is much more common in plants than leucosceptoside B; leucosceptoside A exerts more biological activities than leucosceptoside B even if nothing can be generally concluded about which one is actually the most potent; neither of these compounds can be used as a chemophenetic marker. These three aspects and more are discussed in more depth in this work.

Anti-Zika virus activity and chemical characterization by ultra-high performance liquid chromatography (UPLC-DAD-UV-MS) of ethanol extracts in Tecoma species

Background

Plant species from the genus Tecoma are found in tropical and subtropical regions around the world. Some of them are grown as ornamental plants and others can be used as medicinal plants. In the present study, ethanolic extracts from trunks and leaves of Tecoma species were tested in vitro using assays against the Zika virus.

Methods

There was a total of 8 extracts obtained from different anatomical parts of three Tecoma species. The Tecoma castaneifolia, T. garrocha, T. stans var. angustata and T. stans var. stans were prepared by percolation with ethanol. The antiviral activity was assayed in vitro against the Zika virus by the MTT colorimetric method (n = 3). The UPLC-DAD-MS analysis of ethanolic extracts was performed from all the studied species. The biofractionation of T. stans var. stans trunk extract using different separation techniques led to the isolation of crenatoside compound.

Results

Ethanolic extract from Tecoma species leaves were more active against the Zika virus (EC₅₀ 149.90 to 61.25 μg/mL) when compared to the trunk extracts tested (EC₅₀ 131.0 to 66.79 μg/mL and two were not active). The ethyl acetate and aqueous fractions obtained from T. stans var. stans trunk were active against the Zika virus with EC₅₀ values of 149.90 and 78.98 μg/mL, respectively. Crenatoside is a phenylethanoid glycoside isolated from the ethyl acetate of T. stans var. stans trunk extract. This compound was tested and exhibited EC₅₀ 34.78 μM (21.64 μg/mL), thus demonstrating a better result than the original ethanolic extracts as well as others extracts of Tecoma species, and it was more active than the positive control, ribavirin (386.84 μM). Furthermore, its selectivity index was at least 2.5 times higher than the tested ethanolic extracts and 11.1 times more potent than ribavirin.

Conclusion

The Tecoma species demonstrated interesting in vitro activity against the Zika virus. The crenatoside, phenylethanoid glycoside that was for the first time isolated from Tecoma stans var. stans, exhibited a potent and relevant anti-Zika virus activity, being more active than ribavirin (positive control). The data show that crenatoside, was a promising compound with in vitro antiviral activity against the Zika virus.

Phenylethanoid glycosides from the Schnabelia nepetifolia (Benth.) P.D.Cantino promote the proliferation of osteoblasts

An investigation of the n-BuOH fraction of Schnabelia nepetifolia (Benth.) P.D.Cantino led to the isolation and identification of 12 undescribed phenylethanoid glycosides (nepetifosides A-L) and one undescribed phenylmethanoid glycoside (nepetifoside M), together with 23 known compounds. The structures of these compounds were determined by spectroscopic analyses including two-dimensional nuclear-magnetic-resonance (2D-NMR) spectroscopy and chemical-hydrolysis methods. Nepetifoside F exhibited strong activity that significantly increased osteoblast proliferation at three concentrations of 0.1, 1, and 10 μM. Moreover, nepetifoside C and nepetifoside D exhibited moderate activities in promoting the proliferation of osteoblasts at medium and high concentrations of 1 μM and 10 μM, respectively.

Anti-Respiratory Syncytial Virus Activity of Plantago asiatica and Clerodendrum trichotomum Extracts In Vitro and In Vivo

The herbs Plantago asiatica and Clerodendrum trichotomum have been commonly used for centuries in indigenous and folk medicine in tropical and subtropical regions of the world. In this study, we show that extracts from these herbs have antiviral effects against the respiratory syncytial virus (RSV) in vitro cell cultures and an in vivo mouse model. Treatment of HEp2 cells and A549 cells with a non-cytotoxic concentration of Plantago asiatica or Clerodendrum trichotomum extract significantly reduced RSV replication, RSV-induced cell death, RSV gene transcription, RSV protein synthesis, and also blocked syncytia formation. Interestingly, oral inoculation with each herb extract significantly improved viral clearance in the lungs of BALB/c mice. Based on reported information and a high-performance liquid chromatography (HPLC) analysis, the phenolic glycoside acteoside was identified as an active chemical component of both herb extracts. An effective dose of acteoside exhibited similar antiviral effects as each herb extract against RSV in vitro and in vivo. Collectively, these results suggest that extracts of Plantago asiatica and Clerodendrum trichotomum could provide a potent natural source of an antiviral drug candidate against RSV infection.

Abietane Diterpenoids from the Roots of Clerodendrum trichotomum and Their Nitric Oxide Inhibitory Activities

Twelve new abietane diterpenoids (1-12) and 31 known analogues (13-43) were isolated from a medicinal Chinese herb, Clerodendrum trichotomum Thunberg. The absolute configurations of 1-3 were established on the basis of ECD and X-ray crystallography data, whereas that of 4 was elucidated by comparison of experimental and calculated ECD data. Eight diterpenoids, 15,16-dehydroteuvincenone G (1), trichotomin A (4), 2α-hydrocaryopincaolide F (7), villosin C (20), 15-dehydro-17-hydroxycyrtophyllone A (22), demethylcryptojaponol (38), 6β-hydroxydemethylcryptojaponol (39), and trichotomone (43), exerted inhibitory effects against NO production with IC₅₀ values of 5.6-16.1 μM. The structure-activity relationships of the isolated diterpenoids are also estimated.

Polygonumins A, a newly isolated compound from the stem of Polygonum minus Huds with potential medicinal activities

Polygonumins A, a new compound, was isolated from the stem of Polygonum minus. Based on NMR results, the compound’s structure is identical to that of vanicoside A, comprising four phenylpropanoid ester units and a sucrose unit. The structure differences were located at C-3″″′. The cytotoxic activity of polygonumins A was evaluated on several cancer cell lines by a cell viability assay using tetrazolium dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The compound showed the highest antiproliferative (p < 0.05) activities against K562 (Human Leukaemia Cell Line), MCF7 (Human breast adenocarcinoma cell line), and HCT116 (Colorectal cancer cells) cells. Cytotoxic studies against V79–4 cells were carried out and showed that polygonumins A was toxic at 50 µg/ml, suggesting that this compound may be used as an anticancer drug without affecting normal cells. Polygonumins A also showed promising activity as an HIV-1 protease inhibitor with 56% relative inhibition. Molecular docking results indicated that the compound possesses high binding affinity towards the HIV protease over the low binding free energy range of -10.5 to -11.3 kcal/mol. P. minus is used in Malaysian traditional medicine for the treatment of tumour cells. This is the first report on the use of P. minus as an HIV-1 protease inhibitor.

Scientific validation of medicinal plants used by Yakkha community of Chanuwa VDC, Dhankuta, Nepal

Ethnobotanical knowledge is important among tribal people, but much of the information is empirical due to the lack of scientific validation. The purpose of this study was to document the medicinal plants used by an ethnic group (Yakkha) at Chanuwa VDC of Dhankuta district in Nepal and to validate scientifically in the use of plants based on results of phytochemical, antimicrobial and antioxidant property analyses and available literature reports. Data were collected through interviews of the Yakkha people with the help of a semi-structured questionnaire and the guided field walk method. A total of 30 different medicinal plants were recorded along with their vernacular names (for few plants) used by the Yakkha community’s people. Literature review reveals that most of the plant species described herein have also been used in other countries, too. Among 30 plants selected for this study methanol extract of five ethno-medicinal plants viz., Dendrocnide sinuata, Solanum anguivi, Pogostemon cablin, Boehmeria platyphylla and Clerodendrum trichotomum and ethanol extract of C. trichotomum were subjected for antibacterial and antioxidant properties. The antimicrobial activities were measured using the paper disc diffusion method. The antioxidant properties of plants were measured by DPPH and FRAP reduction assay. Among all extracts, ethanol extract of C. trichotomum and methanol extract of B. platyphylla displayed the highest antibacterial and antioxidant activities, respectively.

The Potential of Sub-Saharan African Plants in the Management of Human Immunodeficiency Virus Infections: A Review

Acquired immunodeficiency syndrome, caused by human immunodeficiency virus (HIV), is a leading cause of mortality and morbidity in Sub-Saharan Africa, particularly in Southern Africa. Phytomedicines are an integral part of African health care. The Southern African flora is composed of at least 23 400 taxa. Despite this richness, only a handful of botanical products have been assessed for activities against HIV. This study aimed to summarize the potential of Sub-Saharan African plants, based on their composition and the established bioactivities, as sources of agents to manage HIV symptoms and as retroviral therapy. At least 109 plant species from 42 families and 94 genera that are found in Southern Africa were shown to have potential or actual activities against HIV. Only 12 of these plant species from 6 families and 10 genera were shown to harbour anti-HIV properties. Phytochemicals that include β-sitosterols, terpenoids, glycosides, saponins, flavonoids, triterpenoids, tannins and alkaloids, which harbour anti-HIV properties, were found to have a near cosmopolitan presence across the plant families in the region. Bioactivities of multiple phytochemicals are comparable to those for standard allopathic antiretroviral drugs. Research to determine the anti-HIV activities of the identified and other plants, including clinical trials, is long overdue.

Terpenoids, flavonoids and caffeic acid derivatives from Salvia viridis L. cvar. Blue Jeans

Three diterpenoids, 1-oxomicrostegiol (1), viroxocin (2), viridoquinone (3), were isolated from the roots of Salvia viridis L. cvar. Blue Jeans. Five known diterpenoids, microstegiol (4), 7α-acetoxy-14-hydroxy-8,13-abietadiene-11,12-dione (5; 7-O-acetylhorminone tautomer), 7α,14-dihydroxy-8,13-abietadiene-11,12-dione (6; horminone tautomer), ferruginol and salvinolonyl 12-methyl ether (7) were also found in the roots together with 1-docosyl ferulate (8), and a mixture of 2-(4'-alkoxyphenyl) ethyl alkanoates (9). Two lupane triterpenoids, 2α-acetoxy-lup-20(29)-en-3β-ol (10), and 3β-acetoxy-lup-20(29)-en-2α-ol (11) were found in the aerial parts together with known compounds, lup-20(29)-ene-2α,3β-diol (12), ursolic acid, oleanolic acid, β-sitosterol and β-sitosterol glucoside. A known phenylpropanoid, trans-verbascoside (or acteoside; 13), was the main constituent in the polar fraction of the aerial part, and it is now reported in the genus Salvia for the first time. Other polyphenolic compounds were cis-verbascoside (14), leucosceptoside A (15), martynoside (16), caffeic acid, 6-O-caffeoyl-glucose (18), rosmarinic acid, salidroside, luteolin-7-O-α-rhamnopyranosyl-(1→6)-β-galactopyranoside, luteolin-7-O-β-galactopyranoside, luteolin-7-O-α-rhamnopyranosyl-(1→6)-β-glucopyranoside, luteolin-7-O-β-glucopyranoside, and apigenin-7-O-β-glucopyranoside. The structures were determined by 1D-, 2D-NMR and HR-ESI-MS techniques. Compounds 6, 10, ferruginol, ursolic acid and oleanolic acid exhibited antibacterial activity against Enterococcus faecalis (ATCC 775) with MIC 50 μM, 25 μM, 50 μM, 12.5 μM, 12.5 μM respectively. Ferruginol, ursolic acid and oleanolic acid were also active against Staphylococcus aureus (ATCC 6571), and Bacillus cereus (ATCC 2599) with MIC 12.5-50 μM. 4 was also active against S.aureus (ATCC 6571) with MIC 50 μM. These values are consistent with previous studies on the antimicrobial activity of Salvia diterpenoids.

Phytochemical profile of Paulownia tomentosa (Thunb). Steud

Paulownia tomentosa, a member of the plant family Paulowniaceae and a rich source of biologically active secondary metabolites, is traditionally used in Chinese herbal medicine. Flavonoids, lignans, phenolic glycosides, quinones, terpenoids, glycerides, phenolic acids, and miscellaneous other compounds have been isolated from different parts of P. tomentosa plant. Recent interest in this species has focused on isolating and identifying of prenylated flavonoids, that exhibit potent antioxidant, antibacterial, and antiphlogistic activities and inhibit severe acute respiratory syndrome coronavirus papain-like protease. They show cytotoxic activity against various human cancer cell lines and inhibit the effects of human cholinesterase, butyrylcholinesterase, and bacterial neuraminidases. Most of the compounds considered here have never been isolated from any other species of plant. This review summarizes the information about the isolated compounds that are active, their bioactivities, and the structure-activity relationships that have been worked out for them.

Diterpenoids and phenylethanoid glycosides from the roots of Clerodendrum bungei and their inhibitory effects against angiotensin converting enzyme and α-glucosidase

Abietane derivatives, bungnates A, B, 15-dehydrocyrtophyllone A and 15-dehydro-17-hydroxycyrtophyllone A, and two phenylethanoid glycosides, bunginoside A and 3″,4″-di-O-acetylmartynoside, together with nine known abietane derivatives and fourteen known phenylethanoid glycosides, were isolated from dried roots of Clerodendrum bungei. Their structures were determined on the basis of detailed spectroscopic analyses and acidic hydrolysis. The absolute configuration of bunginoside A was established from analysis of CD data. Selected compounds were evaluated for inhibitory effects against angiotensin converting enzyme (ACE) and α-glucosidase. 15-Dehydrocyrtophyllone A showed an ACE inhibitory effect, and verbascoside, leucosceptoside A and isoacteoside exhibited strong inhibitory capacity against α-glucosidase.

Clerodendrum serratum (L.) Moon. - a review on traditional uses, phytochemistry and pharmacological activities

ETHNOPHARMACOLOGICAL RELEVANCE

Clerodendrum serratum (L.) Moon. (Verbenaceae) is an important medicinal plant growing in the tropical and warm temperate regions like Africa, Southern Asia; Malaysia and distributed throughout in forests of India and Sri Lanka. It is traditionally valued and reported for treating pain, inflammation, rheumatism, respiratory disorders, fever and malarial fever in India with a long history. To provide a comprehensive overview of the traditional and ethno medicinal uses, phytochemistry and biological activities of C. serratum with clinical and toxicity data and possibly make recommendations for further research.

MATERIALS AND METHODS

All relevant worldwide accepted databases were searched for the terms "Clerodendrum", "Clerodendrum serratum", "Bharangi" and "Cheruthekku" along with the other literature from Indian classical texts and pharmacopoeias. There was no specific timeline set for the search. The accessible literatures available on C. serratum were collected via electronic search using Pubmed, Scopus, Science Direct and traditional books reports on ethnopharmacology and traditional medicines.

RESULTS

C. serratum has played an important role in Indian system of medicine. In addition to the common local use in respiratory diseases, other ethnomedicinal uses include treatment of pain, inflammation, rheumatism and fever especially malarial fever. Scientific studies on extracts and formulations revealed anti-asthmatic, mast cell stabilization and anti-allergic effects of roots of C. serratum. Reported data on pharmacological activities also includes hepatoprotective, anti-oxidant, anti-inflammatory and anticancer potential of the drug. Saponins (terpenoids and steroids), flavonoids and phenolics isolated from roots have been the focus of phytochemical investigations as the biological activity has been ascribed to the saponins, which are known to possess anti-inflammatory and anti-cancer activity. Isolated bioactives from roots like icosahydropicenic acid and ursolic acid have been claimed to offer anti-allergic and hepatoprotective activity.

CONCLUSIONS

Therapeutic potential of roots and leaves of C. serratum has been demonstrated in the conditions like asthma, allergy, fever, inflammation and liver disorders attributed to the presence of various flavonoids, phenolics and saponins present in the drug. Many ethnobotanical claims have been confirmed through modern in-vitro and in-vivo pharmacological studies of different extracts and isolates from plant; however, additional studies on the biomarkers are needed to establish mechanism of action and to validate the traditional use of this drug in clinical practices after proper safety assessment.

Chemical constituents from aerial parts of Caryopteris incana and cytoprotective effects in human HepG2 cells

An ethyl acetate fraction of the aerial parts of Caryopteris incana (Verbenaceae) showed potent cytoprotective effects against damage to HepG2 cells induced by tert-butylhydroperoxide (t-BHP). To search for hepatoprotective components of C. incana, various chromatographic separations of the ethyl acetate soluble fraction of C. incana led to isolation of three phenylpropanoid glycosides, 6‴-O-feruloylincanoside D, 6‴-O-sinapoylincanoside D and caryopteroside, and two iridoid glycosides, incanides A and B, together with 17 known compounds. Structures of these compounds were determined by spectroscopic analyses. The absolute stereochemistry of the caryopteroside was established with the help of circular dichroism data and in comparison with literature data. All isolated substances were determined for their cytoprotective effects against t-BHP-induced toxicity in HepG2 cells. Among the tested compounds, 6'-O-caffeoylacteoside exhibited the most potent cytoprotective activity with an IC50 value of 0.8±0.1 μM against t-BHP-induced toxicity. Structure-activity relationships of the assay results indicated an important role of the catechol moiety in phenylpropanoid, iridoid and flavonoid derivatives in eliciting cytoprotective effects.

Chemical and pharmacological investigation of micropropagated Hygrophila pogonocalyx produced from leaf explants

BACKGROUND

An optimized method for indirect shoot organogenesis from the leaf explants of Hygrophila pogonocalyx, a rare and endemic species in Taiwan, was developed to supply enough quantity of plant materials for the first chemical and pharmacological investigation.

RESULTS

Incubation of the young leaves on Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine (0.5 mg/l) and indole-3-acetic acid (0.1 mg/l) resulted in the best multiplication rate for organogenesis. The average number of adventitious buds per leaf was 22.8 ± 1.9 after 8-week culture. The adventitious buds rooted and developed into plantlets when cultured simply on MS medium. Using this protocol, up to 37,600 plants were produced from a single leaf explant in one year. From the ethanol extract of the leaves of this micropropagated plant, 13 compounds were isolated and identified, including two flavones (1, 11), four flavonols (9, 10, 12, and 13), three phenylethanoid glycosides (6-8), two alkylated glycosides (2-3), and two steroids (4-5). Of these, acteoside (7) exhibited anti-tyrosinase activity in human epidermal melanocytes and luteolin 7-O-β-D-glucopyranoside (11) exhibited the greatest neurocytoprotective activity.

CONCLUSIONS

The method, indirect shoot organogenesis from leaf explants of H. pogonocalyx, could be developed to supply enough quantity of plant materials for the chemical and pharmacological investigation. In the present study, the isolated active compounds may develop for whitening agents or treating neurodegenerative diseases in the future.

Rearranged abietane diterpenoids from the roots of Clerodendrum trichotomum and their cytotoxicities against human tumor cells

The roots of the medicinal ornamental plant Clerodendrum trichotomum yielded a series of rearranged abietane diterpenoids, including three 17(15→16)-abeo-abietane (1-3) and three 17(15→16),18(4→3)-diabeo-abietane (4-6) derivatives. Their structures were elucidated by means of spectroscopic methods. The absolute configuration of (10R,16R)-12,16-epoxy-11,14,17-trihydroxy-6-methoxy-17(15→16)-abieta-5,8,11,13-tetraene-7-one (1) was deduced by a combination of single crystal X-ray diffraction analysis and the observed Cotton effects in its circular dichroism (CD) spectrum. All isolates were tested for their cytotoxicities against five human cancer cell lines (BGC-823, Huh-7, KB, KE-97, and Jurkat). Among them, compounds 4, 6, 9, 10, 12, and 14, each possessing a common 17(15→16),18(4→3)-diabeo-abietane framework, were found to have remarkable cytotoxic effects with IC50 values ranging from 0.83 to 50.99 μM.

Comprehensive review of Clerodendrum phlomidis: a traditionally used bitter

Clerodendrum phlomidis Linn. f., (syn. Clerodendrum multiflorum (Burm.f) O. Kuntze, Volkameria multiflorum Burm. f.) (Lamiaceae) is an important and well known medicinal plant extensively used in Ayurveda and Siddha system of medicine for treatment of various ailments. The popular therapies include on inflammation, diabetes, nervous disorder, asthma, rheumatism, digestive disorders, and urinary disorders as well as a bitter tonic. It was reported that pectolinaringenin, scutellarein, clerodin, clerodendrin, clerosterol, 24beta-ethylcholesta-5,22E,25-triene-3beta-ol, lup-20(29)-en-3-triacontanoate, 4,2',4'-trihydroxy-6'-methoxychalcone-4,4'alpha-D-diglucoside, 7-hydroxyflavone, 7-hydroxyflavanone-7-O-glucoside and alpha-L-rhamnopyranosyl-(1-2)alpha-D-glucopyranosyl-7-O-naringin-4'-O-alpha-D-glucopyranoside-5-methyl ether had been isolated from this plant. The alcoholic and aqueous extracts were reported active as analgesic, antidiarrhoeal, antiplasmodial, hypoglycemic, minor tranquilizers, anti-asthmatic, antifungal, nematicidal, anti-amnestic and anti-arthritic. There are coincidences between some of the traditional usages of this plant and experimentally observed effects of the extracts but very few biological studies available on bioactive fractions and/or pure compounds. This review is an attempt to compile the exhaustive literature on Clerodendrum phlomidis, to highlight, analyze and critically assess the pharmaceutical potential of this underestimated plant in a systematic way.

Chemical and biological investigation of some Clerodendrum species cultivated in Egypt

CONTEXT

Phytochemical investigation of Clerodendrum chinense (Osbeck) Mabberley (Lamiaceae) cultivated in Egypt and evaluation for anti-inflammatory, analgesic, and antipyretic effects of the methanol and chloroform extracts of Clerodendrum chinense, Clerodendrum indicum (L.) Kuntze, Clerodendrum glabrum E. Meyer.

OBJECTIVE

The objective of this study was to investigate the anti-inflammatory, analgesic, and antipyretic effects of the methanol and chloroform extracts of Clerodendrum species under investigation.

MATERIALS AND METHODS

Air-dried powdered leaves of C. chinense were extracted with MeOH 80%. This extract was fractionated with successive portions of chloroform, ethyl acetate and n-butanol. By further fractionation through silica gel, polyamide and reversed phase column chromatography several compounds were isolated which were elucidated by nuclear magnetic resonance (NMR) and mass spectroscopy. For biological study, the powdered leaves of C. chinense, C. indicum and C. glabrum were extracted by chloroform and then extracted with methanol. The acute anti-inflammatory effect of tested extracts of the leaves of Clerodendrum species under investigation was estimated by carrageenan-induced rat paw edema. Antipyretic effect was evaluated and compared with that of paracetamol as standard using the yeast-induced hyperthermia method on female albino rats. Analgesic effect was evaluated and compared with that of Novalgin (metamizol sodium) as standard using an electric current anxious stimulus.

RESULTS

Verbascoside, isoverbascoside, decaffeoylverbascoside, hispidulin, lupeol and icariside B5 were isolated from the leaves of C. chinense for the first time. Cornoside and rengyolone were also isolated. The methanol extract of the leaves of C. chinense and verbascoside showed significant analgesic, anti-inflammatory and antipyretic effects.

CONCLUSION

The present study provided a scientific validation of the traditional claims suggested for C. chinense.

Effects of phenylethanoid glycosides from Digitalis purpurea L. on the expression of inducible nitric oxide synthase

We have isolated four different phenylethanoid glycosides (purpureaside A, desrhamnosyl acteo-side, calceolarioside B and plantainoside D) from the leaves of Digitalis purpurea (foxglove). The effects of these glycosides on activator protein-1 (AP-1)-mediated inducible nitric oxide synthase (iNOS) gene expression in the Raw264.7 macrophage cell line have been studied. Of these four glycosides, purpureaside A potently inhibited iNOS induction by lipopolysaccharide (LPS). Increase in iNOS mRNA by LPS was completely suppressed by purpureaside A. Purpureaside A did not significantly affect LPS-inducible nuclear factor-kB (NF-kB) activation or the nuclear translocation of p65. Moreover, a reporter gene assay using AP-1 specific luciferase reporter revealed that the enhanced activity of AP-1 by LPS was completely abolished in cells treated with purpureaside A. These results demonstrated that purpureaside A inhibited LPS-inducible iNOS expression in macrophages through the suppression of AP-1, but not of NF-kB.

A historical sketch of the discovery and development of HIV-1 integrase inhibitors

The long process of HIV-1 integrase inhibitor discovery and development can be attributed to both the complexity of HIV-1 integration and poor 'integration' of these researches into mainstream investigations on antiretroviral therapy in the mid-1990s. Of note, some fungal extracts investigated during this period contain the beta-hydroxyketo group, later recognised to be a key structural requirement for keto-enol acids (also referred to as diketo acids) and other integrase inhibitors. This review reconstructs (in the general context of the history of AIDS research) the principal steps that led to the integrase inhibitors currently in clinical trials, and discusses possible future directions.

Trichotomoside: A New Antioxidative Phenylpropanoid Glycoside fromClerodendron trichotomum

The structure and antioxidant properties of a new natural glycoside, trichotomoside (1), isolated from Clerodendron trichotomum, were investigated. Trichotomoside was identified as 2-(3-hydroxy-4-methoxyphenyl)ethyl 3-O-(2,3-di-O-acetyl-alpha-L-rhamnopyranosyl)-4-O-[(2E)-3-(3-hydroxy-4-methoxyphenyl)prop-2-enoyl]-beta-D-glucopyranoside. The compound was active towards intracellular reactive oxygen species (ROS) and exhibited DPPH-radical-scavenging effects. The radical-scavenging activity of 1 was found to protect the viability of Chinese hamster lung fibroblasts (V79-4 cells) exposed to H2O2 and gamma-irradiation.

Naturally derived anti-HIV agents

The urgent need for new anti-HIV/AIDS drugs is a global concern. In addition to obvious economical and commercial hurdles, HIV/AIDS patients are faced with multifarious difficulties associated with the currently approved anti-HIV drugs. Adverse effects, the emergence of drug resistance and the narrow spectrum of activity have limited the therapeutic usefulness of the various reverse transcriptase and protease inhibitors that are currently available on the market. This has driven many scientists to look for new anti-retrovirals with better efficacy, safety and affordability. As has always been the case in the search for cures, natural sources offer great promise. Several natural products, mostly of plant origin have been shown to possess promising activities that could assist in the prevention and/or amelioration of the disease. Many of these anti-HIV agents have other medicinal values as well, which afford them further prospective as novel leads for the development of new drugs that can deal with both the virus and the various disorders that characterize HIV/AIDS. The aim of this review is to report new discoveries and updates pertaining to anti-HIV natural products. In the review anti-HIV agents have been classified according to their chemical classes rather than their target in the HIV replicative cycle, which is the most frequently encountered approach. Perusal of the literature revealed that most of these promising naturally derived anti-HIV compounds are flavonoids, coumarins, terpenoids, alkaloids, polyphenols, polysaccharides or proteins. It is our strong conviction that the results and experiences with many of the anti-HIV natural products will inspire and motivate even more researchers to look for new leads from plants and other natural sources.

Inhibition of lipopolysaccharide-inducible nitric oxide synthase expression by acteoside through blocking of AP-1 activation

Acteoside is a phenylpropanoid glycoside with antioxidant and anti-inflammatory activities. We isolated acteoside from Buddlejae Flos, which has been used as a traditional medicine to treat conjunctive congestion and sepsis. The effect of acteoside on the expression of the inducible nitric oxide synthase (iNOS) gene was examined in the Raw264.7 macrophage cell line. An acteoside pretreatment significantly inhibited the release of NO in the cells treated with lipopolysaccharide (LPS). Western blot and RT-PCR analyses revealed that acteoside inhibited the LPS-induced levels of the iNOS protein and mRNA. Activation of the nuclear factor-kappaB (NF-kappaB) and the activator protein-1 (AP-1) is the key step in the signaling pathways mediating iNOS induction. In this study, acteoside selectively suppressed AP-1 activation, which may be essential for iNOS induction in the LPS-treated macrophages. The inhibitory effect of AP-1 activation by acteoside may be associated with the anti-inflammatory effects of Buddlejae Flos.

Antioxidant activity of isoacteoside from Clerodendron trichotomum

The antioxidant properties of isoacteoside, isolated from Clerodendron trichotomum (Verbenaceae), were investigated. This compound scavenged intracellular reactive oxygen species (ROS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and prevented lipid peroxidation. This radical scavenging activity of isoacteoside protected cell viability of Chinese hamster lung fibroblast (V79-4) cells exposed to hydrogen peroxide (H2O2). Furthermore, isoacteoside reduced the apoptotic cells formation induced by H2O2, as demonstrated by the decreased number of sub-G1 hypo-diploid cells and apoptotic cell body formation. However, isoacteoside increased the activities of cellular antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT). Taken together, these findings suggest that isoacteoside, isolated from C. trichotomum, possesses antioxidant properties.

Phenylpropanoid glycosides from Scrophularia scorodonia: in vitro anti-inflammatory activity

Five phenylpropanoid glycosides isolated from Scrophularia scorodonia L. (Scrophulariaceae), namely angoroside A (1), angoroside C (2), angoroside D (3), acteoside (4) and isoacteoside (5), had been evaluated as potential inhibitors of some macrophage functions involved in the inflammatory process. These compounds have been tested in two experimental systems: ionophore-stimulated mouse peritoneal macrophages and human platelets serve as source of COX-1 and 5-LOX, and mouse peritoneal macrophages stimulated with E. coli LPS are the means of testing for COX-2, NO and TNF-alpha activity. None of compounds assayed had a significant effect on LTC(4)-release from calcium ionophore-stimulated mouse peritoneal macrophages. However, the release of PGE(2) by mouse peritoneal macrophages stimulated with calcium ionophore was inhibited by most of these compounds. In the TXB(2)-release assay, acteoside (4), angoroside A (1) and angoroside C (2) showed a significant effect. These five compounds, except angoroside C (2) significantly inhibited LPS-induced PGE(2), NO and TNF-alpha in a concentration-dependent manner. In LPS-stimulated macrophages, the phenylpropanoid glycoside angoroside C (2) only had activity on NO. These results indicate that the pharmacology of these compounds may participate in the anti-inflammatory effect of Scrophularia scorodonia.

Antioxidant Activity of Jionoside D from Clerodendron trichotomum

The antioxidant property of jionoside D, isolated from Clerodendron trichotomum (Verbenaceae), was investigated. This compound showed scavenging activity of intracellular reactive oxygen species and of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, as well as lipid peroxidation inhibitory activity. This radical scavenging activity of jionoside D protected the cell viability of Chinese hamster lung fibroblast (V79-4) cells exposed H2O2. Furthermore, jionoside D reduced the apoptotic cells induced by H2O2, as demonstrated by the decreased number of sub G1 hypo-diploid cells and apoptotic body formation. However, it increased the activities of cellular antioxidant enzymes, superoxide dismutase and catalase. Taken together, these findings suggest that jionoside D, isolated from C. trichotomum, exhibits antioxidant properties.

Angiotensin converting enzyme inhibitory phenylpropanoid glycosides from Clerodendron trichotomum

The stems of Clerodendron trichotomum have been traditionally used for treatment of hypertension in far East Asia including China, Korea, and Japan. Bioassay-guided fractionation and purification of the EtOAc-soluble extract of Clerodendron trichotomum afforded acteoside (1), leucosceptoside A (2), martynoside (3), acteoside isomer (4), and isomartynoside (5). The angiotensin converting enzyme (ACE) activities were significantly inhibited by the addition of these phenylpropanoid glycosides (1-5) in a dose-dependent manner of which IC(50) values were 373+/-9.3 microg/ml, 423+/-18.8 microg/ml, 524+/-28.1 microg/ml, 376+/-15.6 microg/ml, 505+/-26.7 microg/ml, respectively. These results suggest that the antihypertensive effect of Clerodendron trichotomum may be, at least in part, due to ACE inhibitory effect of phenylpropanoid glycosides.

Antioxidative constituents from Buddleia officinalis

Four flavonoids (1-4), a phenylethyl glycoside (5), and a phenylpropanoid glycoside (6) were isolated from the flowers of Buddleia officinalis (Loganiaceae). Their structures were determined by chemical and spectral analysis. Among the isolated compounds, luteolin (1) and acteoside (6) exhibited the most potent antioxidative activity on the NBT superoxide scavenging assay. In addition, compounds 1-6 revealed weak antifungal activity, and no hemolytic activity.