Isoquinoline alkaloids from Mahonia aquifolium stem bark are active against Malassezia spp

In vitro Antifungal Activity of Extracts of Moringa oleifera on Phytopathogenic Fungi Affecting Carica papaya

BACKGROUND: Plants remain the natural sources of efficacious phytonutrients with beneficial assets to mankind against microbial disorders. Diverse folklores have reported the roles of medicinal plants in the remedies of various disorders in man and animals. Metabolites and pesticides from the plant origin are considered better alternatives due to favorable environmental impact as compared to the synthetic counterparts. Significant economic losses and hindrance of global papaya production are due to fungal diseases. Phytochemicals have made medicinal plants become sources of environmentally friendly alternative antimicrobials. AIM: This study aimed at assessing the antifungal activity of leaf extracts of Moringa oleifera against phytopathogenic fungi isolated from Carica papaya. METHODS: n-Hexane, ethyl acetate, ethanol, methanol, and aqueous extracts of M. oleifera leaves were evaluated for their antifungal properties. Agar well-diffusion method was implemented for in vitro screening, minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of the extract types against fungal species of Aspergillus, Penicillium, Rhizopus, and Trichoderma. RESULTS: All the extracts evaluated inhibited fungal growth to some degree, with the aqueous extract exhibiting more inhibitory activities than the organic extracts. There was significant inhibition of fungal development by the tested plant extracts at different concentrations. MIC of the extracts was 15.625 mg/ml while the MFC values ranged between 15.625 and 31.25. In this work, the antifungal activity of M. oleifera was found to be equal or higher than commercially available fungicide, ketoconazole. CONCLUSION: The results of this study indicate that foliole extracts of M. oleifera have potential for use as biofungicides for plant protection against fungal diseases.

The Anticancer Effect of Natural Plant Alkaloid Isoquinolines

Isoquinoline alkaloids-enriched herbal plants have been used as traditional folk medicine for their anti-inflammatory, antimicrobial, and analgesic effects. They induce cell cycle arrest, apoptosis, and autophagy, leading to cell death. While the molecular mechanisms of these effects are not fully understood, it has been suggested that binding to nucleic acids or proteins, enzyme inhibition, and epigenetic modulation by isoquinoline alkaloids may play a role in the effects. This review discusses recent evidence on the molecular mechanisms by which the isoquinoline alkaloids can be a therapeutic target of cancer treatment.

Identification and quantification analysis of the chemical constituents from Mahonia fortune using Q‑Exactive HF Mass Spectrometer and UPLC-ESI-MS/MS

In this research, a comprehensive and innovative method was established for the qualitative and quantitative analysis of the main components in Mahonia fortune (MF). On the one hand, comprehensive insight of the constituents in MF extracts was achieved with a Q‑Exactive HF Mass Spectrometer using data-independent acquisition method. The identification of 17 compounds was based on comparison with authentic reference standards and the deduction of 119 additional compounds both in positive and negative modes was using the MS-dial strategy and comparison with literature data. The proportion of alkaloids and phenols were the most in MF. On the other hand, an ultra-performance liquid chromatographic-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) method for the quantification of 25 components in MF extract were developed and validated. The method established provided satisfactory precision and accuracy; acceptable recovery and stability; a good linearity and a reasonable limit of detection. The MF samples from 11 different sources were detected, and relative principal component analysis were applied to discriminate these samples. The variations of Columbamine, Jatrorrhizine, Palmatine and Berberine were suggested as important indicators of MF quality. This study supplies a novel and comprehensive method for the quality evaluation of MF. This research presents a MS based analytical strategy which shows an application potential in the analysis of the chemical constituents in Traditional Chinese Medicine (TCM).

Acetyleugenol from Acacia nilotica (L.) Exhibits a Strong Antibacterial Activity and Its Phenyl and Indole Analogues Show a Promising Anti-TB Potential Targeting PknE/B Protein Kinases

Acetyleugenol is a phytochemical compound with broad effects against infectious diseases and tumors. Here, we extracted, characterized, and elucidated the structure of acetyeugenol, for the first time, from the leaves of Acacia nilotica (L.)—a well-known medicinal plant. The broad antibacterial potential of acetyleugenol was first confirmed against seven bacterial clinical isolates, which reveal a strong activity against Proteus sp., Salmonella typhi, Staphylococcus aureus, and Streptococcus pneumonia with similar or better zone of inhibition comparing to that of the control amoxicillin. To further investigate its effect against Mycobacterium tuberculosis, acetyleugenol and its indole and phenyl analogues were subjected to molecular docking experiments against two potential tuberculosis drug targets—MtPknE and MtPknB Ser/Thr protein kinases. The results reveal that all of the analogs have improved docking scores compared to the acetyleugenol. The indole analogues EUG-1 and EUG-3 were more effective with better docking scores for MtPknE with −11.08 and −10.05 kcal/mol, respectively. Similar results were obtained for the MtPknB. In contrast, only the EUG-2 phenyl analogue has given rise to similar docking scores for both targets. This opens the door for further comprehensive studies on these acetyleugenol analogues with in vitro and in vivo experiments to validate and get more insights into their mechanisms of action.

Plant-Derived Natural Alkaloids as New Antimicrobial and Adjuvant Agents in Existing Antimicrobial Therapy

Infectious diseases, instigated by pathogenic microorganisms are the cause of numerous health problems in developing countries. Infectious diseases got a place in the list of top ten death causes worldwide. The reason behind that level of severity is antimicrobial resistance. Antimicrobial resistance makes the antimicrobial agents useless when used in the treatment of infectious diseases. Microbes have very smartly achieved resistance against synthetic and semi-synthetic antimicrobial agents for their survival. Therefore, the handling of these diseases has become challenging. The resistance developing power is the reason for their existence since a million years. Due to their highly dangerous nature, proper treatment of infectious diseases has become a topic of concern. This leads the scientists or researchers to focus their research towards natural agents. Plants synthesize secondary metabolites to cope up with biotic and abiotic changes in the environment. Alkaloids are one of the secondary metabolites, synthesized by plants. Alkaloids protect the plant from predators and help them to fight with pathogens. The protecting nature of alkaloids can be used as a strong weapon in battle with resistant microorganisms. The purpose of this review is to provide information about the antimicrobial activity of alkaloids obtained from different plants and their combination with synthetic antimicrobials. Their mechanism of action against microorganisms is also given in the review.

Identification of a multi-component berberine 11-hydroxylase from Burkholderia sp. strain CJ1

Berberine (BBR) is a protoberberine alkaloid extracted from plants such as Coptis japonica (Ranunculaceae). In a previous report, we demonstrated the existence of a 11-hydroxylation pathway employed by BBR-utilizing bacteria for metabolism of BBR. In the present study, we report the identification of the genes brhA, brhB, and brhC as encoding a multicomponent BBR 11-hydroxylase in Burkholderia sp. strain CJ1. BrhA is belonging to the Rieske non-heme iron oxygenase (RO) family, a class of enzymes known to catalyze the first step in bacterial aromatic-ring hydroxylation. We further demonstrate that BrhA activity requires BrhB (ferredoxin reductase) and BrhC (ferredoxin) as electron transport chain components. A BLAST search revealed that BrhA exhibits 38% and 33% sequence identity to dicamba O-demethylase (DdmC; AY786443) and chloroacetanilide herbicides N-dealkylase (CndA; KJ461679), respectively. To our knowledge, this work represents the first report of a bacterial oxygenase catalyzing the metabolism of a polycyclic aromatic-ring alkaloid.

Abbreviations: BBR: berberine; D-BBR: demethyleneberberine; H-BBR: 11-hydroxyberberine; HD-BBR: 11-hydroxydemethyleneberberine; HDBA: 2-hydroxy-3,4-dimethoxybenzeneacetic acid; PAL: palmatine; H-PAL: 11-hydroxypalmatine; BRU: berberrubine; Fd: ferredoxin; FdR: ferredoxin reductase; ETC: electron transport chain

Flavonoids with antibacterial and antioxidant potentials from the stem bark of Uapaca heudelotti

Two flavonol glycosides; U1: naringenin-7-O-glucoside and U2: kaempferol-3-O-glucoside were isolated for the first time, from ethyl acetate fraction of the stem bark of a traditional medicinal plant called Uapaca heudelotti. IR and NMR spectroscopy were used to elucidate the structures of the isolated compound. The two compounds were active against the 7 tested microorganisms; Escherichia coli, Bacillus subtilis, Salmonella typhi, Streptococcus pyogenes, Klebsiella pneumoniae, Staphylococcus aureus and Proteus mirabilis. The zones of inhibition of the compounds ranged from 16 to 23 mm. The MIC value was as low as 6.25 μg/mL against Salmonella typhi, Streptococcus pyogenes, and Bacillus subtilis. The radical scavenging activity of compound U1 and U2 was 80 and 85 % at 240 μg/mL, while that of the standard drug was 98% at 240 μg/mL. The results show an existent possibility of using the plant for the treatment of microbial diseases.

Characterization of Burkholderia sp. strain CJ1, a newly isolated berberine-degrading bacterium from rhizosphere of Coptis japonica

Burkholderia sp. strain CJ1 was newly isolated as berberine (BBR) degrading bacteria from rhizosphere of Coptis japonica. CJ1 had the ability to utilize BBR as the sole carbon source and revealed that BBR metabolism via 11-hydroxylation and demethylenation pathway. It was also revealed that the 11-hydroxylation ability of BBR and palmatine (PAL) has induced by BBR.

Common origin of methylenedioxy ring degradation and demethylation in bacteria

Plants produce many specific secondary metabolites as a response to environmental stress, especially biological stress. These compounds show strong biological activities and high stability against degradation by microbes and animals. Berberine, a benzylisoquinoline alkaloid, is found in many plant species and has strong antimicrobial activity, and is often included in traditional herbal medicines. We previously investigated how berberine is degraded in nature and we isolated two berberine-utilizing bacteria. In this study, we characterized the gene encoding the enzyme that degrades the 2,3-methylenedioxy ring of berberine; this ring is important for its activity and stability. Further characterization of several other berberine-utilizing bacteria and the genes encoding key demethylenation enzymes revealed that these enzymes are tetrahydrofolate dependent and similar to demethylation enzymes such as GcvT. Because the degradation of O-methyl groups or the methylenedioxy ring in phenolic compounds such as lignin, lignan and many other natural products, including berberine, is the key step for the catabolism of these compounds, our discovery reveals the common origin of the catabolism of these stable chemicals in bacteria.

Isolation and identification of berberine and berberrubine metabolites by berberine-utilizing bacterium Rhodococcus sp. strain BD7100

Based on the finding of a novel berberine (BBR)-utilizing bacterium, Rhodococcus sp. strain BD7100, we investigated the degradation of BBR and its analog berberrubine (BRU). Resting cells of BD7100 demethylenated BBR and BRU, yielding benzeneacetic acid analogs. Isolation of benzeneacetic acid analogs suggested that BD7100 degraded the isoquinoline ring of the protoberberine skeleton. This work represents the first report of cleavage of protoberberine skeleton by a microorganism.

A New Antimicrobial Prenylated Benzo-lactone from the Rhizome of Cissus cornifolia

Background:

Medicinal plants remain one of the largest reservoirs of new bioactive compounds. In this study, a new prenylated benzo-lactone (4, 6-dihydroxy-5-methoxy-3-(1, 2, 3, 4, 5-pentahydroxypentyl)-2-benzofuran-1(3H)-one) was isolated from the acetone extracts of the rhizome of Cissus cornifolia. The antimicrobial activity of the compound was evaluated against some microorganisms including Staphylococcus aureus, Salmonella typhi, and Candida albicans.

Materials and Methods:

The acetone extracts of the rhizome of C. cornifolia was separated and purified by various chromatographic techniques. The structure of the isolated compound was characterized by analysis of spectral data including one and two-dimensional nuclear magnetic resonance.

Results:

The isolated compound was characterized as (4, 6-dihydroxy-5-methoxy-3-(1, 2, 3, 4, 5-pentahydroxypentyl)-2-benzofuran-1(3H)-one), it showed activity against 6 out of 10 tested clinical isolates of some microorganisms including S. aureus, S. typhi, and C. albicans. The inhibition zones ranged between 17 mm and 25 mm. The inhibition zones observed compare favorably with the positive control used.

Conclusion:

The compound could serve as a lead for the development of more potent antimicrobial agent. To the best of our knowledge, this is the first report of the isolation and characterization as well as antimicrobial screening of the compound.

The medicinal uses of the genus Mahonia in traditional Chinese medicine: An ethnopharmacological, phytochemical and pharmacological review

ETHNOPHARMACOLOGICAL RELEVANCE

Plants of the genus Mahonia Nuttall (Berberidaceae) have a long history of medical use in Traditional Chinese Medicine (TCM) for the treatment of a wide range of health disorders, such as tuberculosis, periodontitis, dysentery, pharyngolaryngitis, eczema, and wounds. In the theory of TCM, most Mahonia species exert the effects of relieving internal heat, eliminating dampness, removing toxins, suppressing pain, promoting blood circulation, inhibiting cough and alleviating inflammation. The aim of the review is to provide comprehensive summary on ethnopharmacology, phytochemistry, pharmacology, toxicology and clinical trials of Mahonia species used in TCM based on scientific literature. Available scientific evidence supporting the therapeutic effects of Mahonia species in TCM is demonstrated and opportunities for future research are discussed to highlight the scientific gaps in our knowledge that deserves further investigation.

METHODS

The available information on the ethnopharmacological uses in Chinese medicine, phytochemistry, pharmacology and clinical practice of the genus Mahonia was collected from Chinese Herbal Classics, published books, un-published resources, dissertations and various worldwide-accepted scientific databases: CNKI, PubMed, ScienceDirect, SpringerLink, Google Scholar, Wiley, TPL (www.theplantlist.org), SciFinder, and Embase.

RESULTS

A variety of ethnomedical usages of Mahonia have been recorded in ancient Chinese books and references. The phytochemical research of this genus has resulted in the identification of more than 150 chemical constituents, among which alkaloids are predominant. The isolated compounds and crude extracts have been shown to exhibit a wide spectrum of in vitro and in vivo pharmacological effects, including antimicrobial, anti-inflammatory, hepatoprotective, antioxidant, antimutagenic and analgesic properties. Preparations containing Mahonia species have been demonstrated to exert good efficacy for the clinical treatment of dysentery, internal and external hemorrhage, acne vulgaris and chronic pharyngitis, among other diseases.

CONCLUSIONS

The available scientific references demonstrate that the traditional medical uses of some important Mahonia species in TCM have been evaluated in modern pharmacological studies. Isoquinoline alkaloids may contribute to some of the activities shown by the plants of this genus. However, further studies employing scientific technologies and methods are warranted to reveal the phytochemistry of this genus, particularly to detail the active compounds and the underlying mechanisms.

A novel antimicrobial flavonoid from the stem bark of Commiphora pedunculata (Kotschy & Peyr.) Engl

A new flavonoid, 2-(3,5-dihydroxy-4-methoxy-phenyl)-3,5-dihydroxy-8,8-dimethyl-2,3-dihydro-8H-pyrano[3,2]chromen-4-one, together with previously reported epicatechin was isolated from the ethyl acetate soluble fraction of the methanol extract of the stem bark of Commiphora pedunculata. The structures of these compounds were elucidated based on extensive analysis of their spectral data, including 1 and 2D NMR. The compounds were active against 9 out of 12 tested microorganisms including a resistant strain; vancomycin-resistant entrococci (VRE), Escherichia coli, Staphylococcus aureus and Candida albicans. The zones of inhibition ranged between 22 and 34 mm against the microorganisms. The minimum inhibitory concentration was as low as 6.25 μg/mL against Shigella dysentriae, Bacillus cereus and S. aureus while the minimum bactericidal concentration was as low as 50 μg/mL against Pseudomonas aeruginosa, VRE and C. albicans. This is the first report of the isolation of the compound.

Ethnobotany, phytochemistry and pharmacology of Stephania rotunda Lour

ETHNOPHARMACOLOGICAL RELEVANCE

Stephania rotunda Lour. (Menispermaceae) is an important traditional medicinal plant that is grown in Southeast Asia. The stems, leaves, and tubers have been used in the Cambodian, Lao, Indian and Vietnamese folk medicine systems for years to treat a wide range of ailments, including asthma, headache, fever, and diarrhoea.

AIM OF THE REVIEW

To provide an up-to-date, comprehensive overview and analysis of the ethnobotany, phytochemistry, and pharmacology of Stephania rotunda for its potential benefits in human health, as well as to assess the scientific evidence of traditional use and provide a basis for future research directions.

MATERIAL AND METHODS

Peer-reviewed articles on Stephania rotunda were acquired via an electronic search of the major scientific databases (Pubmed, Google Scholar, and ScienceDirect). Data were collected from scientific journals, theses, and books.

RESULTS

The traditional uses of Stephania rotunda were recorded in countries throughout Southeast Asia (Cambodia, Vietnam, Laos, and India). Different parts of Stephania rotunda were used in traditional medicine to treat about twenty health disorders. Phytochemical analyses identified forty alkaloids. The roots primarily contain l-tetrahydropalmatine (l-THP), whereas the tubers contain cepharanthine and xylopinine. Furthermore, the chemical composition differs from one region to another and according to the harvest period. The alkaloids exhibited approximately ten different pharmacological activities. The main pharmacological activities of Stephania rotunda alkaloids are antiplasmodial, anticancer, and immunomodulatory effects. Sinomenine, cepharanthine, and l-stepholidine are the most promising components and have been tested in humans. The pharmacokinetic parameters have been studied for seven compounds, including the three most promising compounds. The toxicity has been evaluated for liriodenine, roemerine, cycleanine, l-tetrahydropalmatine, and oxostephanine.

CONCLUSION

Stephania rotunda is traditionally used for the treatment of a wide range of ailments. Pharmacological investigations have validated different uses of Stephania rotunda in folk medicine. The present review highlights the three most promising compounds of Stephania rotunda, which could constitute potential leads in various medicinal fields, including malaria and cancer.

Bauhinia variegata leaf extracts exhibit considerable antibacterial, antioxidant, and anticancer activities

The present study reports the phytochemical profiling, antimicrobial, antioxidant, and anticancer activities of Bauhinia variegata leaf extracts. The reducing sugar, anthraquinone, and saponins were observed in polar extracts, while terpenoids and alkaloids were present in nonpolar and ethanol extracts. Total flavonoid contents in various extracts were found in the range of 11-222.67 mg QE/g. In disc diffusion assays, petroleum ether and chloroform fractions exhibited considerable inhibition against Klebsiella pneumoniae. Several other extracts also showed antibacterial activity against pathogenic strains of E. coli, Proteus spp. and Pseudomonas spp. Minimum bactericidal concentration (MBC) values of potential extracts were found between 3.5 and 28.40 mg/mL. The lowest MBC (3.5 mg/mL) was recorded for ethanol extract against Pseudomonas spp. The antioxidant activity of the extracts was compared with standard antioxidants. Dose dependent response was observed in reducing power of extracts. Polar extracts demonstrated appreciable metal ion chelating activity at lower concentrations (10-40 μg/mL). Many extracts showed significant antioxidant response in beta carotene bleaching assay. AQ fraction of B. variegata showed pronounced cytotoxic effect against DU-145, HOP-62, IGR-OV-1, MCF-7, and THP-1 human cancer cell lines with 90-99% cell growth inhibitory activity. Ethyl acetate fraction also produced considerable cytotoxicity against MCF-7 and THP-1 cell lines. The study demonstrates notable antibacterial, antioxidant, and anticancer activities in B. variegata leaf extracts.

In vitro Antimicrobial Activity and Phytochemical Screening of Clematis Species Indigenous to Ethiopia

THE LEAVES EXTRACTS OF TWO INDIGENOUS PLANTS OF ETHIOPIA: Clematis longicauda steud ex A. Rich. and Clematis burgensis Engl. are used in Southwestern Ethiopia to treat otorrhoea and eczema. Antimicrobial activity and MIC of crude extracts were determined by disk diffusion and broth dilution. Phytochemical screening was performed on the extracts. The methanol and petroleum ether extracts of both plants showed antibacterial and antifungal activity. Sensitivity of reference strains was concentration dependent. Methanol and petroleum ether extracts of C. burgensis leaves exerted greater inhibitory effects than C. longicauda extracts whereas aqueous extracts of both plants were inactive. The MIC study revealed a concentration of 0.78 mg/ml on bacteria and 3.125 mg/ml on fungi for methanol extract and 1.56 mg/ml on both fungi and bacteria for petroleum ether extract. Phytochemical screening results indicated the presence of proteins, fixed oils, carbohydrates, tannins, saponins, flavonoids, and steroids. Preliminary chromatographic investigation showed fluorescing spots with R(f) values that ranged from 0.05 to 0.96 for phenolic compounds and saponins. As the study is one of the first reports on the two indigenous species of Clematis; isolation, purification and characterization of the different primary and secondary metabolites may further yield alternative options to the microbial chemotherapy.

Chemical composition and antibacterial activity of Indian seagrasses against urinary tract pathogens

Seagrasses have a long history of being used for a variety of remedial purposes, such as the fever, skin diseases, muscle pains, wounds and stomach problems. Hence it is essential to study their bioactive metabolites and medicinal properties when considering their food applications. The chemical composition of six seagrasses were determined and evaluated for their potential to urinary tract infection bacteria (UTI). The chemical composition determined by GC-MS yielded 24 compounds. For the first time 4H-Pyran-4-one-2,3-dihydro-3,5-dihydroxy-6-methyl- (6.68%), d-allose (3.67%) and 5-Caranol, trans,trans-(+)- (2.14%) were identified from Halodule pinifolia. d-Allose is a aldo-hexose (sugar) used as a potential inhibitor of glycosidases and low-calorie carbohydrate sweeteners. Among the six seagrasses tested, H. pinifolia and Cymodocea rotundata exhibited predominant growth inhibitory activity against all the UTI bacteria. This study shows the presence of various biological metabolites in tested seagrasses that can be used effectively in food and pharmacological industries.

Berberine ameliorates TNBS-induced colitis by inhibiting lipid peroxidation, enterobacterial growth and NF-κB activation

Berberine, which is a major constituent of the rhizome of Coptidis japonica (CJ), inhibits IL-8 production in colonic epithelial cells and improves 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice. In our preliminary studies, berberine inhibited lipid peroxidation in liposomes prepared from l-α-phosphatidylcholine as well as TLR-4-linked NF-κB activation in HEK cells. Therefore, to clarify its anticolitic mechanism, we examined the inhibitory effects of berberine in TNBS-induced colitic C3H/HeN and C3H/HeJ mice. Its oral administration inhibited macroscopic score, body weight gain, colon shortening, myeloperoxidase activity, and lipid peroxidation in the colons of TNBS-treated C3H/HeN and C3H/HeJ mice. Berberine inhibited colonic expression of iNOS, COX-2, IL-1β, IL-6, and TNF-α, but increased IL-10 expression in the colons of TNBS-treated C3H/HeN and C3H/HeJ mice. Berberine also inhibited NF-κB activation in TNBS-treated C3H/HeN and C3H/HeJ mice, and inhibited TLR-4 expression in C3H/HeN, but not C3H/HeJ, mice. Treating C3H/HeN and C3H/HeJ mice with berberine significantly reduced the number of Enterobacteriaceae induced by TNBS, but restored the number of Bifidobacteria reduced by TNBS. Furthermore, berberine potently inhibited LPS-induced inflammation in peritoneal macrophages mainly via NF-κB and weakly via MAPKs. Based on these findings, berberine may improve colitis by inhibiting lipid peroxidation, enterobacterial growth and NF-κB activation.

Qualitative phytochemical screening and in vitro antimicrobial effects of methanol stem bark extract of Ficus thonningii (Moraceae)

The methanolic stem bark extract of Ficus thonningii (Moraceae) was subjected to preliminary phytochemical screening and in vitro antimicrobial tests. The phytochemical tests was carried out using standard methods of analysis and these investigations revealed the presence of alkaloids, anthraquinones, carbohydrates, flavonoids, saponins and tannins. The antimicrobial activity of the plant extract was assayed using the agar plate disc diffusion and nutrient broth dilution techniques. Test micro organisms were: Escherichia coli, Klebsiella spp, Pseudomonas aeruginosa, Salmonella typhi (gram-negative), Staphylococcus aureus and Streptococcus spp. (gram-positive). The extracts inhibited the growth of all the test organisms at different concentrations especially against Pseudomonas aeruginosa and Streptococcus spp. which had mean inhibition zone of 33.33+/-7.33 mm and 32.33+/-2.51 mm respectively. The results showed the MIC of 10 mg ml(-1) against pseudomonas and 1.25 against remaining organisms tested. The MBC against Staphylococcus aureus was 2.5 mg ml(-1) and that of Streptococcus spp. was found to be 0.625 mg ml(-1). The extracts showed varied inhibitory activity against the organisms studied.

The in vitro and in vivo apoptotic effects of Mahonia oiwakensis on human lung cancer cells

Both the root and stem bark of Mahonia species were popular folk medicines. The plant has several proven biological activities including anti-bacterial, anti-fungal, and anti-inflammatory effects. However, Mahonia has not been studied for its anticancer effects. In the present study, we made extracts from Mahonia oiwakensis (MOE), a selected species in Taiwan, and investigated their effects on various human lung cells. We found that MOE-induced apoptotic death in human A549 non-small-cell lung carcinoma (NSCLC) cells in a dose- and time-dependent manner. Treatment with the extracts also caused an increase in the sub-G1 fraction of cells, chromosome condensation, and DNA fragmentation. The mitochondrial-mediated pathway was implicated in this MOE-induced apoptosis as evidenced by the activation of the caspase cascade, cleavage of poly (ADP-ribose) polymerase (PARP), disruption of mitochondrial membrane potential, and release of cytochrome C. A higher ratio of Bax/Bcl-2 proteins and cleavage of Bid were also observed in MOE-induced cell apoptosis. In A549 tumor-xenografted nude mice, MOE also retarded in vivo proliferation (P<0.05) and induced apoptosis in tumor cells, as shown by a decrease in Ki-67-positive staining (P<0.05) and increased transferase-mediated dUTP nick-end labeling (TUNEL)-positive staining (P<0.05). In conclusion, MOE inhibits the growth of human lung cancer cells in vitro and in vivo, suggesting that it may have therapeutic potential against human lung cancer.

Free radical scavenging activity and lipoxygenase inhibition of Mahonia aquifolium extract and isoquinoline alkaloids

Roots and stem-bark of Mahonia aquifolium (Oregon grape) (Berberidaceae) are effectively used in the treatment of skin inflammatory conditions.

In the present study, the effect of Mahonia aquifolium crude extract and its two representative alkaloid fractions containing protoberberine and bisbenzylisoquinoline (BBIQ) alkaloids on activity of 12-lipoxygenase (12-LOX), was studied. The reactivity with 1,1-diphenyl-2-picryl-hydrazyl (DPPH), a free stable radical, was evaluated to elucidate the rate of possible lipid-derived radical scavenging in the mechanism of the enzyme inhibition.

The results indicate that although the direct radical scavenging mechanism cannot be ruled out in the lipoxygenase inhibition by Mahonia aquifolium and its constituents, other mechanisms based on specific interaction between enzyme and alkaloids could play the critical role in the lipoxygenase inhibition rather than non-specific reactivity with free radicals.

Antiradical and antioxidant activities of alkaloids isolated from Mahonia aquifolium. Structural aspects

The antioxidant activities of three alkaloids isolated from Mahonia aquifolium--berberine, jatrorrhizine, and magnoflorine--were studied with respect to their structural aspects, particularly the presence and the position of -OH groups, steric conditions of unpaired electron delocalization and parameters of lipophilicity and hydration energy. The antiradical activities of the compounds tested were evaluated as the reactivities toward free stable alpha,alpha'-diphenyl-beta-picrylhydrazyl radical (DPPH). The antioxidant features of the alkaloids tested were investigated in heterogeneous membrane system of DOPC liposomes stressed by peroxidative damage induced by AAPH azoinitiator. Both alkaloids bearing free phenolic groups--jatrorrhizine and magnoflorine--showed better activities in both systems used than berberine not bearing any readily abstractable hydrogen on its skeleton. The former two showed antiperoxidative efficiency in DOPC liposomal membrane comparable to that of an effective scavenger of peroxyl radicals--stobadine-and higher than that of Trolox. We conclude that the favorable antioxidant features of the hydroxylated alkaloids are most probably ensured by the combination of reasonably high antiradical reactivity with high lipophilicity, however, the solvation process was found to markedly interfere with these beneficial effects.

Antifungal Activity of Nor-securinine Against Some Phytopathogenic Fungi

Crude extracts and active principles from medicinal plants have shown potential role in controlling plant diseases in glasshouses as well as in fields as one of the safest and ecofriendly methods. The effect of nor-securinine (an alkaloid) isolated from Phyllanthus amarus has been seen against spore germination of some fungi (Alternaria brassicae, A. solani, Curvularia pennisetti, Curvularia sp., Erysiphe pisi, Helminthosporium frumentacei) as well as pea powdery mildew (Erysiphe pisi) under glasshouse conditions. The sensitivity of fungi to nor-securinine varied considerably. Nor-securinine was effective against most of the fungi. H. frumentacei was more sensitive even at the lowest concentration (1,000 µg/ml). Likewise conidia of E. pisi were also inhibited in partially or completely appressorium formation. Pre-inoculation treatment showed greater efficacy than post-inoculation in inhibiting powdery mildew development on pea plants in a glasshouse. Maximum inhibition occurred at 2000 µg/ml.

Oxygen activation by photoexcited protoberberinium alkaloids fromMahonia aquifolium

Protoberberinium salts, i.e. berberine (I), palmatine (II) and jatrorrhizine (III) prepared from Mahonia aquifolium (Pursh) Nutt. belong to isoquinoline alkaloids possessing interesting biological activity (e.g. antibacterial, antimalarial, antitumor). The characteristic UV/Vis absorption band maxima of I-III iodide salts were found in regions 350 and 425 nm in dimethylsulfoxide (DMSO) and ethanol solvents, and were only negligibly influenced by substitution changes on the C-2 and C-3 positions. The fluorescence intensity of protoberberinium salts monitored in ethanol solutions was significantly lowered by iodide counter-ions, and decreased in the order berberine > palmatine > jatrorrhizine. EPR spectroscopy supplied evidence of the formation of super-oxide anion radicals and singlet oxygen upon irradiation of berberine in oxygenated DMSO solvent. The photochemical generation of O(2) (.-) and (1)O(2) in DMSO solutions of palmatine and jatrorrhizine was substantially lower, and probably reflected the replacement of a photolabile methylenedioxy group at C-2 and C-3 positions in the berberine molecule by two methoxy groups in palmatine, and methoxyl (C-2) and hydroxyl (C-3) substitution in jatrorrhizine. Additionally, the powder EPR spectra of protoberberinium iodides I-III measured at 290 K revealed the presence of single-line EPR signals (g(eff) = 2.0044), which were attributed to hydroperoxidic structures produced by the autoxidation process. The photochemical reactions of protoberbenium salts producing reactive oxygen species after UVA excitation should be integrated in biological activity investigations, as well as in their applications in skin disorder treatment.

Two plant alkaloids isolated from Corydalis longipes as potential antifungal agents

The alkaloids N-methylhydrasteine hydroxylactam and 1-methoxyberberine chloride were isolated from Corydalis longipes. Both alkaloids showed high efficacy individually (in concentration of 50-150 ppm) and also in a 1:1 mixture against spore germination of some fungi, viz. Alternaria alternata, A. brassicae, Curvularia maculans, Curvularia sp., Colletotrichum gloeosporioides, Colletotrichum sp., Helminthosporium speciferum, H. pennisetti, Helminthosporium sp., and Ustilago cynodontis. The antifungal effect of single compounds was dose-dependent. If the mutual ratio of the two components in the mixture was changed from 1:1 to a major content of any of the two compounds, the inhibitory effect on spore germination decreased.

Individual and combined effect of (+/-)-alpha-hydrastine and (+/-)-beta-hydrastine on spore germination of some fungi

(+/-)-alpha-Hydrastine and (+/-)-beta-hydrastine were isolated from Corydalis longipes; both exhibited considerable efficacy against spore germination of some saprophytic and phytopathogenic fungi. While (+/-)-alpha-hydrastine was effective against most of the fungi, Helminthosporium echinoclova was least affected even at the highest dose (150 ppm). (+/-)-beta-Hydrastine was equally effective against several fungi. Mixture of both compounds was more effective than each one individually. Helminthosporium species were again the most resistant toward the mixture. The effect of both alkaloids independently on germination and development of E. pisi conidia on excised pea leaves was also shown. After pre-inoculation with (+/-)-alpha-hydrastine, the effect was more pronounced than the addition post-inoculation; maximum inhibition occurred at 200 ppm. (+/-)-beta-Hydrastine also reduced germination of conidia but was less effective than (+/-)-alpha-hydrastine. The number of primary and secondary branches of conidia and number of appressoria were not affected significantly by either compound.

Antifungal activity of Mahonia aquifolium extract and its major protoberberine alkaloids

The crude extract of Mahonia aquifolium (Berberidaceae) stem bark and its components berberine, palmatine and jatrorrhizine were screened for their inhibitory activity against a variety of dermatophytes and two Candida species of human origin using the in vitro dilution agar plate method. Jatrorrhizine was found to be the most effective against all fungal species tested (MIC ranges from 62.5 to 125 micro g/mL), while the crude extract, berberine, and palmatine exhibited only marginal activity (MIC 500 to >/= 1000 micro g/mL). Dermatophytes were more susceptible to jatrorrhizine than yeasts, and Scopulariopsis brevicaulis appeared the least sensitive species to all the compounds tested. The effects of the alkaloids were compared with those of fluconazole and bifonazole for which the MIC ranges were 12.5 to >100 micro g/mL. Our results suggest that jatrorrhizine may serve as a leading compound for further studies to develop new antifungal agents with highly potent antifungal activity and low host toxicity.

Efficacy of alkaloid (-)-corypalmine against spore germination of some fungi

Inhibition activity of the alkaloid (-)-corypalmine on spore germination of plant pathogenic and saprophytic fungi (Alternaria solani, A brassicicola, A. brassicae, A. melongenae, Curvularia pallescens, C. lunata, C. maculans, Curvularisa sp., Colletotrichum sp., Helminthosporium speciferum, H. frumentacei, H. pennisetti, Heterosporium sp., Penicillum sp., Ustilago cynodontis) was determined. Spore germination of all the tested fungi was inhibited, Heterosporium sp. and Ustilago cynodontis being the most sensitive (complete inhibition of spore germination was observed at the very low concentration of 200 ppm). Curvularia palliscens, C. maculans and Curvularia sp. were less sensitive; complete inhibition of spore germination occurred at 400 ppm.

Antimicrobial activity of berberine--a constituent of Mahonia aquifolium

The antimicrobial activity of the protoberberine alkaloid, berberine, isolated from Mahonia aquifolium, was evaluated against 17 microorganisms including two Gram-negative bacteria--Pseudomonas aeruginosa and Escherichia coli (both resistant and sensitive), two Gram-positive bacteria--Bacillus subtilis and Staphylococcus aureus, Zoogloea ramigera, six filamentous fungi--Penicilium chrysogenum, Aspergillus niger, Aureobasidium pullulans (black and white strain), Trichoderma viride (original green strain and brown mutant), Fusarium nivale, Mycrosporum gypseum and two yeasts--Candida albicans and Saccharomyces cerevisiae. The IC50, minimum inhibitory concentration (MIC), minimum microbicidal concentration (MMC) and minimum microbistatic concentration (MMS) varied considerably depending on the microorganism tested, the sensitivity decreasing as follows: S. aureus > P. aeruginosa S (sensitive) > E. coli S > P. aeruginosa R (resistant) > E. coli R > B. subtilis > Z. ramigera > C. albicans > S. cerevisiae > A. pullulans B (black) > A. pullulans W (white) > T. viride Br (brown) > M. gypseum > A. niger > F. nivale > P. chrysogenum > T. viride G (green).