Natural products – antifungal agents derived from plants

Cambridge University Press v. Georgia State University

Alzheimer's disease (AD) is a main cause of dementia, accounting for up to 75% of all dementia cases. Pathophysiological processes described for AD progression involve neurons and synapses degeneration, mainly characterized by cholinergic impairment. This feature makes acetylcholinesterase inhibitors (AChEi) the main class of drugs currently used for the treatment of AD dementia phase, among which galantamine is the only naturally occurring substance. However, several plant species producing diverse classes of alkaloids, coumarins, terpenes, and polyphenols have been assessed for their anti-AChE activity, becoming potential candidates for new anti-AD drugs. Therefore, this mini-review aimed to recapitulate last decade studies on the anti-AChE activity of plant species, their respective extracts, as well as isolated compounds. The anti-AChE activity of extracts prepared from 54 plant species pertaining 29 families, as well as 36 isolated compounds were classified and discussed according to their anti-AChE pharmacological potency to highlight the most prominent ones. Besides, relevant limitations, such as proper antioxidant assessment, and scarcity of toxicological and clinical studies were also discussed in order to help researchers out with the bioprospection of potentially new AChEi.

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Naturally Occurring Acetylcholinesterase Inhibitors and Their Potential Use for Alzheimer's Disease Therapy.

Lectins are proteins extensively used in biomedical applications with property to recognize carbohydrates through carbohydrate-binding sites, which identify glycans attached to cell surfaces, glycoconjugates, or free sugars, detecting abnormal cells and biomarkers related to diseases. These lectin abilities promoted interesting results in experimental treatments of immunological diseases, wounds, and cancer. Lectins obtained from virus, microorganisms, algae, animals, and plants were reported as modulators and tool markers in vivo and in vitro; these molecules also play a role in the induction of mitosis and immune responses, contributing for resolution of infections and inflammations. Lectins revealed healing effect through induction of reepithelialization and cicatrization of wounds. Some lectins have been efficient agents against virus, fungi, bacteria, and helminths at low concentrations. Lectin-mediated bioadhesion has been an interesting characteristic for development of drug delivery systems. Lectin histochemistry and lectin-based biosensors are useful to detect transformed tissues and biomarkers related to disease occurrence; antitumor lectins reported are promising for cancer therapy. Here, we address lectins from distinct sources with some biological effect and biotechnological potential in the diagnosis and therapeutic of diseases, highlighting many advances in this growing field.

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Lectins, Interconnecting Proteins with Biotechnological/Pharmacological and Therapeutic Applications

Ylang-ylang (Cananga odorata Hook F & Thomson) is one of the plants that are exploited at a large scale for its essential oil which is an important raw material for the fragrance industry The essential oils extracted via steam distillation from the plant have been used mainly in cosmetic industry but also in food industry Traditionally, C odorata is used to treat malaria, stomach ailments, asthma, gout, and rheumatism The essential oils or ylang-ylang oil is used in aromatherapy and is believed to be effective in treating depression, high blood pressure, and anxiety Many phytochemical studies have identified the constituents present in the essential oils of C odorata A wide range of chemical compounds including monoterpene, sesquiterpenes, and phenylpropanoids have been isolated from this plant Recent studies have shown a wide variety of bioactivities exhibited by the essential oils and the extracts of C odorata including antimicrobial, antibiofilm, anti-inflammatory, antivector, insect-repellent, antidiabetic, antifertility and antimelanogenesis activities Thus, the present review summarizes the information concerning the traditional uses, phytochemistry, and biological activities of C odorata This review is aimed at demonstrating that C odorata not only is an important raw material for perfume industry but also considered as a prospective useful plant to agriculture and medicine

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Traditional Uses, Phytochemistry, and Bioactivities of Cananga odorata (Ylang-Ylang)

In humans, many diseases are associated with the accumulation of free radicals. Antioxidants can scavenge free radicals and minimize their impact. Therefore, the search for naturally occurring antioxidants of plant origin is imperative. Here, we aimed to investigate the antioxidant and free radical scavenging properties of methanolic extracts from Tabebuia pallida (T. pallida) stem bark (TPSB), root bark (TPRB), leaves (TPL), and flowers (TPF). The antioxidant and free radical scavenging activity were determined by several standard methods using spectrophotomer. Total phenolic and flavonoid contents were estimated using Folin-Ciocalteu reagent and aluminum chloride colorimetric assay methods, respectively. Among the extracts, TPL showed the highest total antioxidant capacity followed by TPRB, TPF, and TPSB. Based on DPPH and hydroxyl radical scavenging activity, TPL showed strong scavenging activity (91.05 ± 1.10 and 62.00 ± 0.57) with IC50 of 9.20 ± 0.28 and 46.00 ± 2.84 μg/mL, respectively when compared with standard BHT (IC50 of 7.00 ± 0.25 μg/mL) and CA (75.00 ± 0.14 μg/mL). These results suggest that TPL had the highest radical scavenging activity among the extractives that closely resembled the standard’s. In lipid peroxidation inhibition assay, TPL exhibited the most potent inhibitory activity (83.18 ± 2.12 %) with IC50 of 12.00 ± 2.12 μg/mL, which closely resembled standard CA (IC50 of 10.50 ± 0.28 μg/mL). Also, the reducing capacity on ferrous ion was in the following order: TPL > TPRB > TF > TPSB. The phenolic and flavonoid contents of TPL were higher than other extractives. A positive correlation (p value <0.001) was observed between phenolic content and free radical (DPPH· and ·OH) scavenging efficiencies and lipid peroxidation inhibition activity. Methanolic extract of T. pallida leaf is a potential source of natural antioxidants and serves as an effective free radical scavenger and/or inhibitor. Hence, T. pallida might be a good plant-based pharmaceutical product for several diseases caused by free radicals.

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In vitro antioxidant and free radical scavenging activity of different parts of Tabebuia pallida growing in Bangladesh

Alzheimer’s disease (AD), one of the major causes of dementia, is an overwhelming neurodegenerative disease that particularly affects the brain, leading to memory loss and impairment of language and judgment capacity. The aim of the present study was to investigate the antioxidant and anticholinesterase properties of the leaves of Elatostema papillosum (EPL) and correlate with their phytochemical profiles, which are relevant to the treatment of AD. The dried coarse powder of EPL was extracted with 80% methanol (EPL-M80) by cold extraction method. The resultant EPL-M80 was assessed for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity by the Ellman method. The antioxidant activity was determined by DPPH (1, 1-diphenyl-2-picrylhydrazyl) and hydroxyl radical scavenging assays. Quantitative phytochemical (phenolic and flavonoid contents) analysis of endogenous substances in EPL-M80 was performed by standard spectrophotometric methods. EPL-M80 significantly (p < 0.05) inhibited AChE and BChE activity with IC50 of 165.40 ± 4.01 and 213.81 ± 3.57 μg/mL, respectively in a dose-dependent manner. Additionally, EPL-M80 exhibited strong radical scavenging activity against DPPH (IC50 = 32.35 ± 0.68 μg/mL) and hydroxyl radical (IC50 = 19.67 ± 1.42 μg/mL) when compared to that of standards. EPL-M80 was found to be rich in phenolic (23.74 mg gallic acid equivalent/g of dry extract) and flavonoid (31.18 mg quercetin equivalent/g of dry extract) content. Furthermore, a positive correlation (p < 0.001) was observed between the total phenolics and antioxidant as well as the anticholinesterase potential. The marked inhibition of AChE and BChE, and potent antioxidant activity of the leaves of Elatostema papillosum highlight its potential to provide an effective treatment for AD.

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In vitro antioxidant and cholinesterase inhibitory activities of Elatostema papillosum leaves and correlation with their phytochemical profiles: a study relevant to the treatment of Alzheimer's disease.

In last three decades, several studies were carried out on the d-galactose-specific lectin of Momordica charantia seeds (MCL). In the present study, in vitro growth inhibition (8–23 %) at different concentrations (6–24 μg/ml) of MCL was observed against Ehrlich ascites carcinoma (EAC) cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. MCL also showed 28, 45, and 75 % growth inhibitions against EAC cells when administered 1.2, 2.0, and 2.8 mg/kg/day (i.p.), respectively for five consequent days in vivo in mice. After lectin treatment, the level of red blood cell and hemoglobin was increased significantly with the decrease of white blood cell and maintained the normal level when compared with EAC-bearing control and normal mice without EAC cells. Although MCL caused cell cycle arrest at G0/G1 phase of EAC cells, any irregular shape or apoptotic morphological alterations in the lectin-treated EAC cells was not observed by an optical and fluorescence microscope. Lectin showed toxicity against brine shrimp nauplii with an LC50 value of 49.7 μg/ml. Four out of seven pathogenic bacteria were agglutinated by MCL in the absence of inhibitory sugar d-lactose/d-galactose. In conclusion, MCL showed strong cytotoxic effect and therefore can be used as a potent anticancer chemotherapeutic agent.

A. H. M. Khurshid Alam

Papers

In vitro antioxidant and free radical scavenging activity of different parts of Tabebuia pallida growing in Bangladesh

In vitro antioxidant and cholinesterase inhibitory activities of Elatostema papillosum leaves and correlation with their phytochemical profiles: a study relevant to the treatment of Alzheimer's disease.

Momordica charantia Seed Lectin: Toxicity, Bacterial Agglutination and Antitumor Properties

Antifertility Activity of Pergularia daemia

Antibacterial and cytotoxic compounds from the bark of Cananga odorata.