Glycosmis pentaphylla (Retz.) DC. has been traditionally used to cure various illnesses and conditions such as fever, eczema and rheumatism. The present study was designed to evaluate the antimicrobial and DNA binding activities of the alkaloids isolated from the plant. Leaves and stem bark of G. pentaphylla were extracted by continuous extraction using hexane and acetone prior to acid base extraction. Screening of alkaloids available was done by Thin Layer Chromatography (TLC). Fractionation by column chromatography was employed to separate the extract into fractions of alkaloid compounds. Antimicrobial active alkaloids were screened by TLC Agar Overlay Assay against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Candida albicans ATCC 90028. The alkaloids were isolated by using column chromatography and were authenticated by comparing their TLC profile, maximum wavelength for UV absorption in methanol and melting point to that of authentic alkaloids. The identification of the alkaloids was further confirmed by their NMR spectral data. The antimicrobial activity of the alkaloids was determined quantitatively by means of their Minimum Inhibitory Concentration (MIC) and Minimum Microbiocidal Concentration (MMC) by using broth microdilution assay. Antimicrobial combination effects between the active alkaloids and selected antimicrobial agents, which were erythromycin and vancomycin was studied by cherkerboard assay and determined by their Fractional Inhibitory Concentration Index (FICI). DNA binding activity of the alkaloids was investigated by method using restriction enzymes and specially designed 1.5 kb DNA fragment. Three antimicrobial active alkaloids labeled as GP3-3, GP6-2 and GP11-2 were detected, isolated, authenticated and identified as arborinine, arborine and skimmianine respectively. Antimicrobial activity of arborinine and arborine were ranged between 250 ?g/mL and 1000 ?g/mL. Arborinine and arborine showed lowest MIC values of 250 ?g/mL and 500 ?g/mL respectively which were against C. albicans. Arborine displayed high MIC values against all other microbes while arborinine was weak against S. aureus, E. coli and P. aeruginosa. No synergistic effect was observed from the combination of the alkaloids with the selected antimicrobial agents against Gram positive, S. aureus, Gram negative E. coli and fungi, C. albicans. However, partial synergy was reported for all interactions between arborine and antimicrobial agents against S. aureus and interaction between arborinine and ketoconazole against C. albicans. Additive effect was only produced when arborine was combined with vancomycin while antagonism was observed for the interaction between arborine and ciprofloxacin when tested against E. coli. All alkaloids displayed photo activated DNA binding activity by strength in the order of arborine, arborinine and skimmianine.

The genus Alpinia belongs to the family of Zingiberaceae. It is distributed in tropical Africa, Asia, and particularly in Southeast Asia. The study was conducted to evaluate the antimicrobial and skin cytotoxic activities of Alpinia javanica, Alpinia galanga and Alpinia conchigera extracts. The crude extracts of A. javanica, A. galanga and A. conchigera were evaluated for their antimicrobial activity against human dermatophytes, gram positive and gram negative bacteria, and multidrug/methicillin resistant Staphylococcus aureus (MRSA) by using Disk Diffusion assay. Minimum inhibitory concentrations (MICs), minimum bactericidal and fungicidal concentrations (MBC and MFC) of A. javanica, A. galanga and A. conchigera crude extracts were determined based on a broth micro-dilution method in 96-microwell plates. The acetoxychavicol acetate (ACA), which is the major compound in Alpinia, was analysed and identified by using thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). The toxic or hazardous effects of Alpinia extracts on normal mouse fibroblast (NIH/3T3) and normal human epidermal keratinocytes - adult (NHEK-a) cell lines were assessed through MTT assay. Overall, all extracts of A. javanica, A. galanga and A. conchigera showed good antibacterial and antifungal activities. However, hexane extract from A. javanica rhizome demonstrated strongest antibacterial activity with inhibition zone of 26 ± 0 mm against Staphylococcus aureus. In general, rhizome extracts of A. galanga showed strongest antibacterial effect as compared to leaf extracts. Overall, all Alpinia extracts showed good antibacterial activities against multidrug/methicillin-resistant Staphylococcus aureus (MRSA), however hexane extract from rhizome of A. javanica demonstrated strongest antibacterial activity against all strains of MRSA, followed by dichloromethane (DCM) and methanol extracts. The antibacterial activity of hexane extract was 29 ± 0.60 mm against MRSA. Similarly, A. javanica rhizome extracts demonstrated strongest antifungal activity against Microsporum canis. Antifungal activities of hexane extracts were 20 ± 0 mm and 21 ± 1.5 mm, against Trichophyton rubrum and M. canis respectively. All extracts of A. conchigera showed significant antifungal activities; however, compared to the A. javanica and A. galanga extracts, the inhibition is weaker. In MIC, MBC and MFC study, hexane and methanol extracts showed significant inhibitory effects as compared to DCM extract. According to TLC analysis, all hexane and methanol extracts of A. javanica, A. galanga and A. conchigera rhizome showed the presence of ACA at the Rf value of 0.61. HPLC analysis also confirmed the presence of ACA compound in all rhizomes extracts (except DCM) of A. javanica, A. galanga and A. conchigera. HPLC fingerprint showed identical ACA peak at retention time of 7.66 min (standard) and 7.66 min for hexane and methanol extracts of A. javanica, A. galanga and A. conchigera rhizome extracts. The present study showed that all extracts of A. javanica, A. galanga and A. conchigera were not toxic towards both NIH/3T3 and NHEK-a cell lines. In conclusion, the findings demonstrated that Alpinia could be a cheaper and feasible source to fight against pathogens that causes fungal skin infections such as tinea and MRSA infections but further research should be carried out on the isolation of specific bioactive compounds and their characterizations.

Amphiphilic molecules play a key role in the stabilization of many of the colloids. It is, therefore, very important to understand the interfacial behaviour of these molecules and to select the proper ones for the proper activity. Synthetic surfactants and emulsifiers are widely used in many of our foods and pharmaceutical formulation, but, it becomes very important to replace them by natural molecules with good health records. Five medicinal plants which are Syzygium aromaticum, Entada spiralis, Trigonella foenum-graecum, Elephantopus scaber and Andrographis paniculata were selected for this study. The crude extract of the plants were prepared by maceration method. Solvents with different polarity were used for the extraction. The physical properties, in particular the surface activity of the extracts were evaluated and compared. Properties of emulsions prepared from the crude extracts were then investigated. Homogenization was carried out from 20% palm oil with 10% crude extract. The antimicrobial activities of the extracts against two Gram-positive Bacillus subtilis and Staphylococcus aureus and two Gram-negative bacteria Pseudomonas aeruginosa and Escherichia coli were investigated. Both the disc diffusion (qualitative) and tube macrodilution (quantitative) assays were employed for the determination of antimicrobial activity. The extracts of E. spiralis and S. aromaticum from ethanol-water 1:1 gave stable emulsions at least up to six months when kept at room temperature. The surface active compounds, if present among the components extracted will be adsorbed differently at the interface producing different extent of emulsion stability. All extracts were able to inhibit the growth of one or more of the bacteria. The patterns of inhibition varied with the type of plant extract, the solvent used for extraction and the organism tested. S. aureus, was the most susceptible to all plant extracts while E. coli was the most resistant microorganism. The highest antibacterial activity was observed from S. aromaticum extract with lowest minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 0.39 mg/mL and 0.78 mg/mL, respectively against B. subtilis. It can be concluded that the extracts from S. aromaticum and E. spiralis have the potential to be used for the preparation of stable pharmaceutical emulsions by providing both emulsifying and antimicrobial actions.

Significant finding of Rutaceae alkaloids in search of new drugs have led to an important strategy to overcome the problems of resistance and side effects associated with conventional antibiotics. In this study, leaves of the plant Ruta angustifolia (L.) Pers. was extracted and fractionated by using column chromatography. Through bioassay-guided isolation, combined fraction of R33 and R48, fraction RC-8 and Rd-10 yielded a total of three antimicrobial active alkaloids. These isolated alkaloids were then identified by means of Thin Layer Chromatography profile, melting point and maximum wavelength for UV absorption in methanol (UV? max-MeOH) in comparison with authentic alkaloids. The identification was further confirmed by 1H NMR and 13C NMR spectroscopic data and was characterized as acridone, furoquinoline and 4-quinolone so named arborinine, skimmianine and graveoline respectively. The antimicrobial activites of arborinine and graveoline were tested against Staphylococcus aureus, Enterococcus fecalis, Helicobacter pylori, Escherichia coli, Pseudomonas aeruginosa and Candida albicans of ATCC strains. Broth microdilution assay of both alkaloids gave Minimum Inhibitory Concentration (MIC) values ranging from 250 µg/ml to 1000 µg/ml. Minimum Bactericidal Concentration (MBC) values were recorded at 1000 µg/ml and more than 1000 µg/ml. The MIC and MBC of the compounds was compared with that of the standard antibiotics namely norfloxacin, ciprofloxacin, vancomycin, erythromycin and ketoconazole. Antibacterial combination effects of graveoline with erythromycin or vancomycin were studied against S. aureus, E. fecalis and E. coli by means of Fractional Inhibitory Concentration (FIC) index. All the tested combination resulted in additive effects with FIC index ranged from 0.75 to 1.02. Antifungal combination effects of arborinine and ketoconazole was experimented against C. albicans and showed synergistic interaction with FIC index of 0.5. Bacterial DNA-binding properties of the three alkaloids were investigated against double-stranded DNA with various restriction enzymes. The investigation revealed that these three alkaloids mostly affect the cleavage activity of the restriction enzymes which contains 5’-TpA sequence rather than 5’-ApT sequence in their recognition pattern and potential crosslink sites under UV exposure. These isolated alkaloids were screened to possess antimicrobial activity through DNA synthesis inbition mechanism and might need to combine with other agent to enhance its inhibitory effects.