The incidence of fungal infections has increased significantly, so contributing to morbidity and mortality. This is caused by an increase in antimicrobial resistance and the restricted number of antifungal drugs, which retain many side effects. Candida species are major human fungal pathogens that cause both mucosal and deep tissue infections. Recent evidence suggests that the majority of infections produced by this pathogen are associated with biofilm growth. Biofilms are biological communities with a high degree of organization, in which micro-organisms form structured, coordinated and functional communities. These biological communities are embedded in a self-created extracellular matrix. Biofilm production is also associated with a high level of antimicrobial resistance of the associated organisms. The ability of Candida species to form drug-resistant biofilms is an important factor in their contribution to human disease. The study of plants as an alternative to other forms of drug discovery has attracted great attention because, according to the World Health Organization, these would be the best sources for obtaining a wide variety of drugs and could benefit a large population. Furthermore, silver nanoparticles, antibodies and photodynamic inactivation have also been used with good results. This article presents a brief review of the literature regarding the epidemiology of Candida species, as well as their pathogenicity and ability to form biofilms, the antifungal activity of natural products and other therapeutic options.

Candida species: current epidemiology, pathogenicity, biofilm formation, natural antifungal products and new therapeutic options

The therapeutic potential of Cassia surattensis in reducing free radical-induced oxidative stress and inflammation particularly in hepatic diseases was evaluated in this study. The polyphenol rich C. surattensis seed extract showed good in vitro antioxidant. C. surattensis seed extract contained total phenolic content of 100.99 mg GAE/g dry weight and there was a positive correlation (r > 0.9) between total phenolic content and the antioxidant activities of the seed extract. C. surattensis seed extract significantly (p < 0.05) reduced the elevated levels of serum liver enzymes (ALT, AST, and ALP) and relative liver weight in paracetamol-induced liver hepatotoxicity in mice. Moreover, the extract significantly (p < 0.05) enhanced the antioxidant enzymes and glutathione (GSH) contents in the liver tissues, which led to decrease of malondialdehyde (MDA) level. The histopathological examination showed the liver protective effect of C. surattensis seed extract against paracetamol-induced histoarchitectural alterations by maximum recovery in the histoarchitecture of the liver tissue. Furthermore, histopathological observations correspondingly supported the biochemical assay outcome, that is, the significant reduction in elevated levels of serum liver enzymes. In conclusion, C. surattensis seed extract enhanced the in vivo antioxidant status and showed antihepatotoxic activities, which is probably due to the presence of phenolic compounds.

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Redox Control of Antioxidant and Antihepatotoxic Activities of Cassia surattensis Seed Extract against Paracetamol Intoxication in Mice: In Vitro and In Vivo Studies of Herbal Green Antioxidant

Oil palm plantations have expanded rapidly in recent decades. This large-scale land-use change has had great ecological, economic, and social impacts on both the areas converted to oil palm and their surroundings. However, research on the impacts of oil palm cultivation is scattered and patchy, and no clear overview exists. We address this gap through a systematic and comprehensive literature review of all ecosystem functions in oil palm plantations, including several (genetic, medicinal and ornamental resources, information functions) not included in previous systematic reviews. We compare ecosystem functions in oil palm plantations to those in forests, as the conversion of forest to oil palm is prevalent in the tropics. We find that oil palm plantations generally have reduced ecosystem functioning compared to forests: 11 out of 14 ecosystem functions show a net decrease in level of function. Some functions show decreases with potentially irreversible global impacts (e.g. reductions in gas and climate regulation, habitat and nursery functions, genetic resources, medicinal resources, and information functions). The most serious impacts occur when forest is cleared to establish new plantations, and immediately afterwards, especially on peat soils. To variable degrees, specific plantation management measures can prevent or reduce losses of some ecosystem functions (e.g. avoid illegal land clearing via fire, avoid draining of peat, use of integrated pest management, use of cover crops, mulch, and compost) and we highlight synergistic mitigation measures that can improve multiple ecosystem functions simultaneously. The only ecosystem function which increases in oil palm plantations is, unsurprisingly, the production of marketable goods. Our review highlights numerous research gaps. In particular, there are significant gaps with respect to socio-cultural information functions. Further, there is a need for more empirical data on the importance of spatial and temporal scales, such as differences among plantations in different environments, of different sizes, and of different ages, as our review has identified examples where ecosystem functions vary spatially and temporally. Finally, more research is needed on developing management practices that can offset the losses of ecosystem functions. Our findings should stimulate research to address the identified gaps, and provide a foundation for more systematic research and discussion on ways to minimize the negative impacts and maximize the positive impacts of oil palm cultivation.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/brv.12295

A review of the ecosystem functions in oil palm plantations, using forests as a reference system

Use of essential oils for controlling Candida albicans growth has gained significance due to the resistance acquired by pathogens towards a number of widely-used drugs. The aim of this study was to test the antifungal activity of selected essential oils against Candida albicans in liquid and vapour phase and to determine the chemical composition and mechanism of action of most potent essential oil. Minimum Inhibitory concentration (MIC) of different essential oils in liquid phase, assayed through agar plate dilution, broth dilution & 96-well micro plate dilution method and vapour phase activity evaluated through disc volatilization method. Reduction of C. albicans cells with vapour exposure was estimated by kill time assay. Morphological alteration in treated/untreated C. albicans cells was observed by the Scanning electron microscopy (SEM)/Atomic force microscopy (AFM) and chemical analysis of the strongest antifungal agent/essential oil has been done by GC, GC-MS. Lemon grass (Cymbopogon citratus) essential oil exhibited the strongest antifungal effect followed by mentha (Mentha piperita) and eucalyptus (Eucalyptus globulus) essential oil. The MIC of lemon grass essential oil in liquid phase (288 mg/l) was significantly higher than that in the vapour phase (32.7 mg/l) and a 4 h exposure was sufficient to cause 100% loss in viability of C. albicans cells. SEM/AFM of C. albicans cells treated with lemon grass essential oil at MIC level in liquid and vapour phase showed prominent shrinkage and partial degradation, respectively, confirming higher efficacy of vapour phase. GC-MS analysis revealed that lemon grass essential oil was dominated by oxygenated monoterpenes (78.2%); α-citral or geranial (36.2%) and β-citral or neral (26.5%), monoterpene hydrocarbons (7.9%) and sesquiterpene hydrocarbons (3.8%). Lemon grass essential oil is highly effective in vapour phase against C. albicans, leading to deleterious morphological changes in cellular structures and cell surface alterations.

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Liquid and vapour-phase antifungal activities of selected essential oils against candida albicans: microscopic observations and chemical characterization of cymbopogon citratus

Antibacterial metal ions, such as Ag+, Zn2+ and Cu2+, have been extensively used in medical implants and devices due to their strong broad spectrum of antibacterial activity. However, it is still a controversial issue as to whether they can show the desired antibacterial activity while being toxic to mammalian cells. It is very important to balance their antibacterial effectiveness with minimal damage to mammalian cells. Toward this end, this study is to identify the suitable concentrations of these three ions at which they can effectively kill two types of clinically relevant bacteria (Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli)) but show no obvious cytotoxicity on fibroblasts. Such concentration ranges are found to be 2.5 × 10–7 M–10–6 M, 10–5 M–10–4 M, and 10–5 M–10–4 M for Ag+, Zn2+, and Cu2+, respectively. Investigation of their antibacterial mechanism shows that these three metal ions all show antibacterial property through a mechanism of damaging bacterial cell membranes by the...

Concentration ranges of antibacterial cations for showing the highest antibacterial efficacy but the least cytotoxicity against mammalian cells: implications for a new antibacterial mechanism.

The antimicrobial activities of the methanolic extracts of Euphorbia hirta L leaves, flowers, stems and roots were evaluated against some medically important bacteria and yeast using the agar disc diffusion method. Four Gram positive (Staphylococcus aureus, Micrococcus sp., Bacillus subtilis and Bacillus thuringensis), four Gram negative (Escherichia coli, Klebsiella pneumonia, Salmonella typhi and P. mirabilis) and one yeast (Candida albicans) species were screened. Inhibition zones ranged between 16-29 mm. Leaves extract inhibited the growth of all tested microorganisms with large zones of inhibition, followed by that of flowers, which also inhibited all the bacteria except C. albicans. The most susceptible microbes to all extracts were S. aureus and Micrococcus sp. Root extract displayed larger inhibition zones against Gram positive bacteria than Gram negative bacteria and had larger inhibition zones compared to stem extract. The lowest MIC values were obtained with E. coli and C. albicans (3.12 mg/mL), followed by S. aureus (12.50 mg/mL) and P. mirabilis (50.00 mg/mL). All the other bacteria had MIC values of 100.00 mg/mL. Scanning Electron Microscopic (SEM) studies revealed that the cells exposed to leaf extract displayed a rough surface with multiple blends and invaginations which increased with increasing time of treatment, and cells exposed to leaf extract for 36 h showed the most damage, with abundant surface cracks which may be related to final cell collapse and loss of function. Time-kill assay of C. albicans indicated a primarily fungicidal effect at 1- and 2-fold MIC. E. hirta extracts had LC(50) values of 0.71, 0.66, 0.41 and 0.03 mg/mL for stems, leaves, roots and flowers, respectively against Artemia salina. Hence, these plants can be used to discover new bioactive natural products that may serve as leads in the development of new pharmaceuticals.

Assessment of Euphorbia hirta L. leaf, flower, stem and root extracts for their antibacterial and antifungal activity and brine shrimp lethality.

This study investigates antioxidant activity of Cassia fistula seeds extract. The antioxidant potential of this extract was evaluated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and xanthine oxidase inhibition assay. The IC50 values were calculated for DPPH and xanthine oxidase assays in order to evaluate the antioxidant efficiency of C. fistula seed extract. Total phenolic and flavonoid content were also determined. The seeds extract were exhibit antioxidant activity 59.587% with an IC50 value of 11.07 mg/ml in DPPH radical scavenging method. Furthermore, the C. fistula seeds extracts scavenged the superoxide radical generated by the xanthine/xanthine oxidase system. The percentage of xanthine oxidase inhibition activity of seed extract and allopurinol was 64.56 and 93.24%, respectively. The amount of total phenolic and flavonoid content was 474.25 ± 25.89 µg GAE/mg extract and 70.86 ± 1.43 µg catechin/mg extract respectively. High performance thin layer chromatography (HPTLC) screening indicates the presence of both free radical scavenging and phenolic compounds in C. fistula seed extract. The colored bands developed on TLC chromatogram visualized after spraying the plates with Folin-Ciocalteu’s and DPPH reagents which represent phenolic and radical scavenging compounds, respectively.

	 

	Key words: Cassia fistula seed, antioxidant activity, xanthine oxidase inhibition, phenolic compounds.

https://www.academicjournals.org/article/article1380629083_Jothy et al.pdf

Phytochemicals screening, DPPH free radical scavenging and xanthine oxidase inhibitiory activities of Cassia fistula seeds extract

Pharmacological activity, phytochemical analysis and toxicity of methanol extract of Etlingera elatior (torch ginger) flowers

In situ TEM and SEM studies on the antimicrobial activity and prevention of Candida albicans biofilm by Cassia spectabilis extract

The fungicidal activity of Cassia spectabilis leaf extracts was investigated using the disk diffusion technique and the broth dilution method. The extract showed a favorable antimicrobial activity against Candida albicans with a minimum inhibition concentration(MIC)value of 6.25 mg ⁄ ml. Apart from the fungicidal effects, imaging using scanning electron microscopy(SEM)was done to determine the major alterations in the microstructure of the C. albicans. The main abnormalities noted in the SEM studies were the alterations in morphology and complete collapse of the yeast cells after 36 h of exposure to the extract. The in vitro time-kill study performed using the leaf extract at 1 ⁄ 2, 1 or 2 times of the MIC significantly inhibited the yeast growth with a noticeable drop in optical density (OD) of yeast culture, thus confirming the fungicidal effect of the extract on C. albicans. In addition, in vivo antifungal activity studies on candidiasis in mice showed a 5-fold decrease in Candida in kidneys and blood samples in the groups of animals treated with the extract(2.5 g ⁄ kg body weight). In an acute toxicity study using mice, the acute minimum fatal dose of the extract was greater than 2000 mg ⁄ kg, and we found no histopathological changes in macroscopic examination by necropsy of mice treated with extract. We conclude that the extract may be safely used as an anticandidal agent.

Z. Zuraini

Papers

Assessment of Euphorbia hirta L. leaf, flower, stem and root extracts for their antibacterial and antifungal activity and brine shrimp lethality.

Phytochemicals screening, DPPH free radical scavenging and xanthine oxidase inhibitiory activities of Cassia fistula seeds extract

Pharmacological activity, phytochemical analysis and toxicity of methanol extract of Etlingera elatior (torch ginger) flowers

In situ TEM and SEM studies on the antimicrobial activity and prevention of Candida albicans biofilm by Cassia spectabilis extract

Fungicidal effect and oral acute toxicity of Cassia spectabilis leaf extract.