Sub-acute toxicological and behavioural effects of two candidate therapeutics,cinnamaldehyde and eugenol,for treatment of ESBL producing-quinolone resistant pathogenic Enterobacteriaceae

Present study deals with evaluation of antibacterial activity of cinnamaldehyde and eugenol against both extended-spectrum-β-lactamase (ESBL)-producing and quinolone resistant (QR) (ESBL-QR) pathogenic Enterobactericeae along with determination of its in vivo toxicity level in a murine model to investigate their pharmacological potential. Broth microdilution assay was used to determine minimum inhibitory concentrations (MICs) of cinnamaldehyde (CIN), eugenol (EG) and traditional antibiotics against ESBL-QR Enterobactericeae. Sub-acute oral toxicity study (14 days) was carried out in Swiss albino mice to evaluate any toxicological and behavioural effect viz novelty suppressed feeding (NSF), novel object recognition (NOR), tail suspension test (TST) and social interaction test of cinnamaldehyde and eugenol. Cinnamaldehyde and eugenol demonstrated mode-MIC of 7.28 and 7.34 μg/mL among maximum numbers of Escherichia coli (32.1%) and 0.91 and 3.67 μg/mL among maximum numbers of Klebsiella  pneumoniae (24.2%) isolates, respectively. For haematological and toxicological analyses, after 14 days of oral administration of cinnamaldehyde (0.91–10 mg/kg) and eugenol (7.34–70 mg/kg), blood was collected from the murine model, while histological examinations were performed on liver and kidney. There was no alteration in food and water intake among treated animals. Toxicological and behavioural studies displayed good safety profiles of cinnamaldehyde and eugenol. The results indicated potential antibacterial efficacy of cinnamaldehyde and eugenol against pathogenic ESBL-QR Enterobacteriaceae, without any significant toxicological and behavioural effects.     

丁香酚对压疮致病菌金黄色葡萄球菌及其耐药菌的抑菌作用及机制

目的 明确丁香酚对压疮致病菌金黄色葡萄球菌Staphylococcus aureus的体外抑菌作用及机制。方法 采用微量肉汤稀释法和和生长曲线确定丁香酚对金黄色葡萄球菌的抑菌活性；通过碱性磷酸酶（AKP）活性、细菌核酸蛋白泄漏的检测，细菌超微结构的扫描和透射电镜观察以及菌体对碘化丙啶（PI）和N-菲酰-次巯基-L-丙氨酸（NPN）的摄取来探讨丁香酚处理后金黄色葡萄球菌细胞膜的通透性和完整性；以结晶紫染色法和实时荧光定量PCR法研究丁香酚对菌体生物被膜（BF）生成、成熟以及菌体黏附、侵袭相关毒力因子表达水平的影响。结果 丁香酚对金黄色葡萄球菌标准菌和耐甲氧西林金葡菌（MRSA）的最低抑菌浓度（MIC）分别为0.25、0.125 mg/mL。丁香酚处理后可以提高细菌培养液中核酸、蛋白浓度及AKP的活性；菌体出现皱缩和破裂，菌体内膜和外膜中分别出现PI和NPN荧光，菌体结构破坏和荧光强度与丁香酚浓度呈正相关。丁香酚能够抑制金黄色葡萄球菌菌株BF的生成，且对成熟BF具有明显清除作用，显著降低BF生成相关基因agrA、sarA、cidA和icaA及黏附因子clfA、clfB、fnbA和fnbB的基因表达水平；与标准菌株相比，丁香酚对MRSA的作用更明显。结论 丁香酚对金黄色葡萄球菌标准菌株和耐药菌株均具有显著抗菌作用，可破坏菌体细胞结构，改变细胞膜通透性和完整性，抑制BF的生成，并对成熟BF具有清除作用，抑制细菌BF及黏附侵袭相关毒力因子的转录和表达，可能是艾灸促进压疮创面修复的机制之一。     

Inhibitory effect of N-ethyl-3-amino-5-oxo-4-phenyl-2,5-dihydro-1H-pyrazole-1-carbothioamide on Haemophilus spp. planktonic or biofilm-forming cells

During this study, we have investigated in vitro activity of N-substituted-3-amino-5-oxo-4-phenyl-2,5-dihydro-1H-pyrazole-1-carbothioamide derivatives with N-ethyl, N-(4-metoxyphenyl) and N-cyclohexyl substituents against Gram-negative Haemophilus influenzae and H. parainfluenzae bacteria. A spectrophotometric assay was used in order to determine the bacterial growth and biofilm formation using a microtiter plate to estimate minimal inhibitory concentration (MIC) and minimal biofilm inhibitory concentration (MBIC). Among the tested N-substituted pyrazole derivatives, only N-ethyl-3-amino-5-oxo-4-phenyl-2,5-dihydro-1H-pyrazole-1-carbothioamide showed a significant in vitro activity against both planktonic cells of H. parainfluenzae (MIC = 0.49–31.25 μg ml^?1) and H. influenzae (MIC = 0.24–31.25 μg ml^?1) as well as biofilm-forming cells of H. parainfluenzae (MBIC = 0.24–31.25 μg ml^?1) and H. influenzae (MBIC = 0.49 to ≥31.25 μg ml^?1). The pyrazole compound exerted higher inhibitory effect both on the growth of planktonic cells and biofilm formation by penicillinase-positive and penicillinase-negative isolates of H. parainfluenzae than the activity of commonly used antibiotics such as ampicillin. No cytotoxicity of the tested compound in vitro at concentrations used was found. The tested pyrazole N-ethyl derivative could be considered as a compound for the design of agents active against both pathogenic H. influenzae and opportunistic H. parainfluenzae, showing also anti-biofilm activity. This appears important because biofilms are determinants of bacterial persistence in long-term and recurrent infections recalcitrant to standard therapy.     

Biofilm Eradication Kinetics of the Ultrashort Lipopeptide C12‐OOWW‐NH2 Utilizing a Modified MBEC Assay™

In this study, we report the antimicrobial planktonic and biofilm kill kinetics of ultrashort cationic lipopeptides previously demonstrated by our group to have a minimum biofilm eradication concentration (MBEC) in the microgram per mL (μg/mL) range against clinically relevant biofilm‐forming micro‐organisms. We compare the rate of kill for the most potent of these lipopeptides, dodecanoic (lauric) acid‐conjugated C₁₂‐Orn‐Orn‐Trp‐Trp‐NH₂ against the tetrapeptide amide H‐Orn‐Orn‐Trp‐Trp‐NH₂ motif and the amphibian peptide Maximin‐4 via a modification of the MBEC Assay^? for Physiology & Genetics (P&G). Improved antimicrobial activity is achieved upon N‐terminal lipidation of the tetrapeptide amide. Increased antimicrobial potency was demonstrated against both planktonic and biofilm forms of Gram‐positive micro‐organisms. We hypothesize rapid kill to be achieved by targeting of microbial membranes. Complete kill against established 24‐h Gram‐positive biofilms occurred within 4 h of exposure to C₁₂‐OOWW‐NH₂ at MBEC values [methicillin‐resistant Staphylococcus epidermidis (ATCC 35984): 15.63 μg/mL] close to the values for the planktonic minimum inhibitory concentration (MIC) [methicillin‐resistant Staphylococcus epidermidis (ATCC 35984): 1.95 μg/mL]. Such rapid kill, especially against sessile biofilm forms, is indicative of a reduction in the likelihood of resistant strains developing with the potential for quicker resolution of pathogenic infection. Ultrashort antimicrobial lipopeptides have high potential as antimicrobial therapy.     

Total syntheses of surinone B,alatanones A–B,and trineurone A

The total syntheses of four polyketides, surinone B (1), alatanones A–B (2–3), and trineurone A (4) were accomplished through an efficient and unified strategy via one-pot C-acylation reaction coupling 1,3-cyclohexadiones with EDC-activated acids under mild conditions. Alatanone A (2) was found to be a potent anti-microbial agent against Gram-positive and Gram-negative bacteria with MIC 31.25 μg/ml while alatanone B (3) was found to be a potent anti-fungal agent against Cladosporium cladosporioides with MIC 62.5 μg/ml compared to cycloheximide MIC 125 μg/ml. Our methodology allows performing kilogram scale of these scarce polyketides for the development of new antimicrobials.     

Antityrosinase and antimicrobial activities from Thai medicinal plants

Various dermatological disorders and microbial skin infection can cause hyperpigmentation. Therefore, screenings for whitening and antimicrobial agents from Thai medicinal plants have been of research interest. Seventy-seven ethanol plant extracts were investigated for antityrosinase activity, eleven samples showed the tyrosinase inhibition more than 50 % were further preliminary screening for antimicrobial activity by agar disc diffusion and broth micro-dilution methods. Artocarpus integer (Thunb.) Merr. (Moraceae) root extract, which showed the potential of tyrosinase inhibition with 90.57 ± 2.93 % and antimicrobial activity against Staphylococcus aureus, S. epidermidis, Propionibacterium acnes and Trichophyton mentagophytes with inhibition zone as 9.10 ± 0.00, 10.67 ± 0.09, 15.25 ± 0.05 and 6.60 ± 0.17 mm, respectively was selected for phytochemical investigation. Three pure compounds were isolated as artocarpin, cudraflavone C and artocarpanone. And artocarpanone exhibited anti-tyrosinase effect; artocarpin and cudraflavone C also showed the potential of antibacterial activity against S. aureus, S. epidermidis and P. acnes with MIC at 2, 4 and 2 μg/ml, respectively and MBC at 32 μg/ml for these bacteria. So, these pure compounds are interesting for further study in order to provide possibilities of new whitening and antibacterial development. This will be the first report of phytochemical investigation of A. integer root.     

Chemical constituents from the roots of Feroniella lucida

A new furanocoumarin named lucidafuranocoumarin A (7) together with 13 known coumarins (1–6, 8–14) and four known alkaloids (15–18) was isolated from the roots of Feroniella lucida. Their structures were elucidated on the basis of spectroscopic analysis. Some of the isolates were evaluated for their biological activities, and compound 18 showed strong cytotoxicity against KB (IC₅₀ = 0.637 μg/ml) and NCI-H187 (IC₅₀ = 0.094 μg/ml) human cancer cell lines, antimalarial activity against Plasmodium falciparum (IC₅₀ = 0.336 μg/ml), and antituberculosis activity against Mycobacterium tuberculosis (MIC = 6.25 μg/ml).     

A new anthraquinone and a new naphthoquinone from the whole plant of Spermacoce latifolia

A phytochemical study on the whole plant of Spermacoce latifolia led to the isolation of a new anthraquinone, 1,2,6-trihydroxy-5-methoxy-9,10-anthraquinone (1), and a new naphthoquinone, (2R)-6-hydroxy-7-methoxy-dehydroiso-α-lapachone (2), together with three known anthraquinones (3–5). Their structures were established on the basis of detailed spectroscopic analysis, including one- and two-dimensional NMR, ESI–MS, and HR–ESI–MS techniques. All the compounds were isolated from S. latifolia for the first time. Compounds 1, 2, 4, and 5 showed significant antibacterial activity toward Bacillus subtilis with MIC values ranging from 0.9 to 31.2 μg/ml, and compound 4 aslo exhibited antibacterial activity against Bacillus cereus with a MIC value 62.5 μg/ml. Compound 1 was further revealed to show significant in vitro α-glucosidase inhibitory activity with IC₅₀ value of 0.653 mM.     

Antimicrobial activity of pomegranate fruit constituents against drug-resistant Mycobacterium tuberculosis and β-lactamase producing Klebsiella pneumoniae

Abstract

Context: The global surge in multi-drug resistant bacteria and the imminence of tuberculosis pandemic necessitate alternative therapeutic approaches to augment the existing medications. Pomegranate, the fruit of Punica granatum Linn. (Punicaceae), widely recognized for potency against a broad spectrum of bacterial pathogens, deserves further investigation in this respect.

Objective: This study determines the therapeutic potential of pomegranate juice, extracts of non-edible peel prepared with methanol/water, and its four polyphenolic constituents, namely caffeic acid, ellagic acid, epigallocatechin-3-gallate (EGCG) and quercetin, against drug-resistant clinical isolates.

Materials and methods: Phenotypic characterisation of Mycobacterium tuberculosis, extended-spectrum β-lactamase (ESBL) and KPC-type carbapenemase producing Klebsiella pneumoniae was performed by biochemical and molecular methods. Resistance profiles of M. tuberculosis and K. pneumoniae were determined using LJ proportion and Kirby–Bauer methods, respectively. Pomegranate fruit extracts, and the compounds, were evaluated at a dose range of 1024–0.5?µg/mL, and 512–0.25?µg/mL, respectively, to determine minimum inhibitory (MIC) and bactericidal concentrations (MBC) against the drug-resistant isolates by the broth micro-dilution method.

Results: The peel extracts exhibited greater antimycobacterial activity (MIC 64–1024?μg/mL) than the potable juice (MIC 256?-?>?1024?μg/mL). EGCG and quercetin exhibited higher antitubercular (MIC 32–256?μg/mL) and antibacterial (MIC 64–56?μg/mL) potencies than caffeic acid and ellagic acid (MIC 64–512?μg/mL).

Discussion and conclusion: The pomegranate fruit peel and pure constituents were active against a broad panel of M. tuberculosis and β-lactamase producing K. pneumoniae isolates. EGCG and quercetin need further investigation for prospective application against respiratory infections.     

Antibacterial effects of 18 medicinal plants used by the Khyang tribe in Bangladesh

Context: The resistance of bacteria to antibiotics is raising serious concern globally. Asian medicinal plants could improve the current treatment strategies for bacterial infections. The antibacterial properties of medicinal plants used by the Khyang tribe in Bangladesh have not been investigated.

Objective: The present study examines the antibacterial properties of 18 medicinal plants used by the Khyang tribe in day-to-day practice against human pathogenic bacteria.

Materials and methods: Leaves, bark, fruits, seeds, roots and rhizomes from collected plants were successively extracted with hexane, ethyl acetate and ethanol. The corresponding 54 extracts were tested against six human pathogenic bacteria by broth microdilution assay. The antibacterial mode of actions of phytoconstituents and their synergistic effect with vancomycin and cefotaxime towards MRSA was determined by time-killing assay and synergistic interaction assay, respectively.

Results and discussion: Hexane extract of bark of Cinnamomum cassia (L.) J. Presl. (Lauraceae) inhibited the growth of MRSA, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii with MIC values below 100 µg/mL. From this plant, cinnamaldehyde evoked at 4?×?MIC in 1?h an irreversible decrease of MRSA count Log10 (CFU/mL) from 6 to 0, and was synergistic with vancomycin for MRSA with fractional inhibitory concentration index of 0.3.

Conclusions: Our study provides evidence that the medicinal plants in Bangladesh have high potential to improve the current treatment strategies for bacterial infection.     

Gamma radiation synthesis optimization of a novel polymer and its possible applications in antimicrobial and antitumor fields

A new monomer, m-keto acetyl naphthalene acrylic acid (KANAc) was synthesized from reactants of maleic anhydride and 1-acetyl naphthalene. This monomer was polymerized by exposure to γ-rays ⁶⁰Co. The effects of dose, dose rate, monomer concentration, and temperature on polymerization yield have been investigated. KANAc and its poly(KANAc) were characterized by different techniques. The results indicated that the average molecular weights ranged from 1.1 to 7 × 10⁵ g/mol and having a good stability. The poly(KANAc) has showed broad spectrum antimicrobial activity. Minimal inhibitory concentration (MIC) values ranged from 96 to 186 μg/ml. At MIC and 0.5× MIC concentrations, poly(KANAc) exerted variable effects on 24.4 Gy in vitro γ-irradiated and non-irradiated tested strains. Poly(KANAc) altered cell membrane permeability, induced genomic DNA damage and adverse effects on total protein. Furthermore, it proved to induce in vitro cytotoxicity against different human carcinoma cell lines with 50% inhibitory concentrations (IC₅₀) values in the range of 9.9–32.2 μg/ml. The outcome results have been good and promising in both antimicrobial and antitumoral fields.     

Cytotoxic flavonoids from the fruits of Derris indica

Chemical investigation of the ethyl acetate extract from the fruits of Derris indica has led to the isolation of a new furanoflavonoid derivative, 4′-hydroxypinnatin (1), and five known compounds. Pinnatin (2) showed strong cytotoxicity against cholangiocarcinoma (KKU-100) and human hepatoma (HepG2) cell lines with IC₅₀ values of 6.0 ± 2.7 and 9.0 ± 4.1 μg/ml, respectively, and showed maximal cell killing effect of about 88–90%. Flavone 5 exhibited the most cytotoxicity against KKU-100 but it showed moderate efficacy (Emax = 50.7%).     

The antimicrobial activity of Cbf-K<Subscript>16</Subscript> against MRSA was enhanced by β-lactamantibiotics through cell wall non-integrity

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as one of the most important pathogens both in health care and in community-onset infections. Cbf-K₁₆, a cathelicidin-like antimicrobial peptide, presented broad antimicrobial activity during our previous studies. We evaluated the potential for synergy of Cbf-K₁₆ with ceftazidime/ampicilin against MRSA, which was resistant to these two antibiotics with the minimum inhibitory concentration more than 64 μg/ml. The combinations showed a synergistic effect by a checkerboard assay with a fractional inhibitory concentration index ≤0.5. The killing curves of the combination treatment against MRSA showed that CFU counts decreased rapidly within 4 h by almost five logs, while single medication groups and the control group exhibited little inhibitory effect. In addition, in a mice bacteremia model, studies indicated that the combination treatment significantly prolonged the survival time of mice infected with MRSA, with a death protection rate of 80 %. Flow cytometry analysis and transmission electron microscopy indicated that combination-treated MRSA was completely ruptured with the cellular contents leaked out. The synergistic effect showed that Cbf-K₁₆ selectively killed cells with non-integrity induced by cell wall inhibition antibiotics, suggesting that Cbf-K₁₆ is a potential therapeutic agent and adjuvant for antimicrobial chemotherapy.     

Halogenated benzoate derivatives of altholactone with improved anti-fungal activity

Altholactone exhibited the anti-fungal activity with a high MIC value of 128 μg ml^?1 against Cryptococcus neoformans and Saccharomyces cerevisiae. Fifteen ester derivatives of altholactone 1–15 were modified by esterification and their structures were confirmed by spectroscopic methods. Most of the ester derivatives exhibited stronger anti-fungal activities than that of the precursor altholactone. 3-Bromo- and 2,4-dichlorobenzoates (7 and 15) exhibited the lowest minimal inhibitory concentration (MIC) values against C. neoformans at 16 μg ml^?1_, while the 4-bromo-, 4-iodo-, and 1-bromo-3-chlorobenzoates (11–13) displayed potent activity against S. cerevisiae with MIC values of 1 μg ml^?1. In conclusion, this analysis indicates that the anti-fungal activity of altholactone is enhanced by addition of halogenated benzoyl group to the 3-OH group.     

Effects of Novel Diarylpentanoid Analogues of Curcumin on Secretory Phospholipase A2, Cyclooxygenases,Lipo‐oxygenase,and Microsomal Prostaglandin E Synthase‐1

Arachidonic acid and its metabolites have generated a heightened interest due to their significant role in inflammation. Inhibiting the enzymes involved in arachidonic acid metabolism has been considered as the synergistic anti‐inflammatory effect. A series of novel curcumin diarylpentanoid analogues were synthesized and evaluated for their inhibitory effects on activity of secretory phospholipase A₂, cyclooxygenases, soybean lipo‐oxygenase as well as microsomal prostaglandin E synthase‐1. Among the curcumin analogues, compounds 3 , 6 , 9 , 12, and 17 exhibited strong inhibition of secretory phospholipase A₂ activity, with IC₅₀ values ranging from 5.89 to 11.02 μm . Seven curcumin analogues 1 , 3 , 6 , 7 , 9 , 11, and 12 showed inhibition of cyclooxygenases‐2 with IC₅₀ values in the range of 46.11 to 94.86 μm , which were lower than that of curcumin. Compounds 3 , 6 , 7 , 12, and 17 showed strong inhibition of lipo‐oxygenase enzyme activity. Preliminary screening of diarylpentanoid curcumin analogues for microsomal prostaglandin E synthase‐1 activity revealed that four diarylpentanoid curcumin analogues 5 , 6 , 7 , and 13 demonstrated higher inhibition of microsomal prostaglandin E synthase‐1 activity with IC₅₀ ranging from 2.41 to 4.48 μm , which was less than that of curcumin. The present results suggest that some of these diarylpentanoid analogues were able to inhibit the activity of these enzymes. This raises the possibility that diarylpentanoid analogues of curcumin might serve as useful starting point for the design of improved anti‐inflammatory agents.     

A new phenolic enamide and a new meroterpenoid from marine alga-derived endophytic fungus Penicillium oxalicum EN-290

Abstract

Ten secondary metabolites (1–10) including a new phenolic enamide, methyl (Z)-3-(3,4-dihydroxyphenyl)-2-formamidoacrylate (1), and a new meroterpenoid, 15-hydroxydecaturin A (2), were characterized from the EtOAc extracts of the marine alga-derived endophytic fungus Penicillium oxalicum EN-290. The structures of these compounds were elucidated on the basis of 1D and 2D NMR experiments and the absolute configuration of compound 2 was confirmed by electronic circular dichroism quantum calculations. Compound 1 showed potent activity against Staphylococcus aureus with an MIC value of 2.0 μg/ml, which is stronger than that of the positive control (chloromycetin, with an MIC 4.0 μg/ml). This compound also showed activity against harmful algal bloom causative species Nitzschia closterium with inhibition zones of 20, 16, and 10 mm at 20, 10, and 5 mg/ml, respectively. Interestingly, so far, this type of anti-HAB metabolites has only been found in the algal-derived isolate of P. oxalicum. It could probably be a defense of this fungus against environmental stress and threat of survival.     

Exploration of antimicrobial potential of essential oils of Cinnamomum glanduliferum,Feronia elephantum,Bupleurum hamiltonii and Cyclospermum leptophyllum against foodborne pathogens

Abstract

Context: Cinnamomum glanduliferum (Wall.) Meissn. (Lauraceae), Feronia elephantum Correa (Rutaceae), Bupleurum hamiltonii Balak (Apiaceae) and Cyclospermum leptophyllum (Pers.) Sprague ex Britton & P. Wilson (Apiaceae) are common species found in Northwest Himalaya and are widely used as folk medicine. The study became more interesting because hitherto there are no reports on the antimicrobial screening of these species with specific chemical composition.

Objective: The antimicrobial potential of the essential oils of C. glanduliferum, F. elephantum, B. hamiltonii and C. leptophyllum against some commonly occurring foodborne pathogenic and spoilage bacteria was explored in this study.

Materials and methods: Antimicrobial screening studies of essential oils were performed against some Gram-positive and Gram-negative bacterial strains using broth-dilution methods. Each essential oil was prepared by serial double dilution method to get final concentrations ranging from 0.85--440.0?µg/ml in a 96 microtiter plate.

Results: The in vitro studies revealed that C. glanduliferum oil was very active against Gram-negative bacteria, A. salmonicida (MIC 1.72?µg/ml), E. coli (MIC 3.43?µg/ml), and P. aeruginosa (MIC 3.43?µg/ml) as compared to the standards gentamicin and kanamicin. Oil of C. leptophyllum exhibited better inhibitory activity profile against Gram-positive S. aureus (MIC 3.43?μg/ml) and Gram-negative E. herbicola (MIC 1.72?μg/ml) and P. aeruginosa (MIC 3.43?μg/ml) as compared to the standards.

Discussion and conclusion: These results reveal that these essential oils may be used in the treatment of diseases caused by the foodborne pathogenic and spoilage bacteria. Their importance as potential medicinal agents is based on the antimicrobial findings.     

Antibacterial activity of Thai herbal extracts on acne involved microorganism

Ethyl acetate and methanol extracts of 18 Thai medicinal plants were investigated for their antibacterial activity against Propionibacterium acnes, Stapylococcus aureus, and S. epidermidis. Thirteen plant extracts were capable of inhibiting the growth of P. acnes and S. epidermidis, while 14 plant extracts exhibited an inhibitory effect on S. aureus. Based on the broth dilution method, the ethyl acetate extract of Alpinia galanga (L.) Wild. (Zingiberaceae) rhizome showed the strongest antibacterial effect against P. acnes, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 156.0 and 312.0 µg/mL, respectively. On the basis of bioassay-guided purification, the ethyl acetate extract was isolated to afford the antibacterial active compound, which was identified as 1′-acetoxychavicol acetate (1′-ACA). 1′-ACA had a strong inhibitory effect on P. acnes with MIC and MBC values of 62.0 and 250.0 µg/mL, respectively. Thus, 1′-ACA was used as an indicative marker for standardization of A. galanga extract using high performance liquid chromatography. These results suggest that A. galanga extract could be an interesting agent for further studies on an alternative treatment of acne.     

Screening of in vitro antimicrobial activity of plants used in traditional Indonesian medicine

Context: In many regions of Indonesia, there are numerous traditional herbal preparations for treatment of infectious diseases. However, their antimicrobial potential has been poorly studied by modern laboratory methods.

Objective: This study investigates in vitro antimicrobial activity of 49 ethanol extracts from 37 plant species used in Indonesian traditional medicine for treatment against Candida albicans, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus.

Materials and methods: The plants were collected from the Biopharmaca collection garden, Bogor, Indonesia. The plant material was dried, finely grounded, extracted using ethanol, concentrated, and the dried residue was dissolved in 100% DMSO. Antimicrobial activity was determined in terms of a minimum inhibitory concentration (MIC) using a broth microdilution method in 96-well microplates.

Results: The extract of Orthosiphon aristatus (Blume) Miq. (Lamiaceae) leaf produced the strongest antimicrobial effect, inhibiting the growth of C. albicans (MIC 128?μg/mL), S. aureus (MIC 256?μg/mL), E. faecalis (MIC 256?μg/mL) and P. aeruginosa (MIC 256?μg/mL). The leaf extract of Woodfordia floribunda Salisb. (Lythraceae) also exhibited significant effect against C. albicans (MIC 128?μg/mL), S. aureus (MIC 256?μg/mL) and E. faecalis (MIC 256?μg/mL). Rotheca serrata (L.) Steane &; Mabb. (Lamiaceae) leaf extract inhibited the growth of S. aureus (MIC 256 µg/mL) and C. albicans (MIC 256 µg/mL).

Discussion and conclusions: The leaf extract of O. aristatus and W. floribunda exhibited a significant anti-candidal effect. Therefore, both of these plants can serve as prospective source materials for the development of new anti-candidal agents.     

New cyclomyrsinol diterpenes from Euphorbia aellenii with their immunomodulatory effects

Chloroform–acetone extract of the aerial parts of Euphorbia aellenii Rech. f. (Euphorbiaceae) was investigated for its diterpenoidal constituents. This led to the isolation of two new and one known cyclomyrsinol-type diterpenes 1–3. The structures were elucidated on the basis of 1D and 2D ¹H and ¹³C NMR techniques, and in vitro immunomodulatory activity was evaluated by standard proliferation of human peripheral blood lymphocytes. Results showed that all the three compounds were found to inhibit lymphocyte proliferation significantly (p < 0.05) at 50 μg/ml concentration. Among them, compound 2 showed more activity against phytohemagglutinin-activated T-cell proliferation with an IC₅₀ of 40.4 ± 9.35 μg/ml.