Compounds from the Petroleum Ether Extract of Wedelia chinensis with Cytotoxic, Anticholinesterase, Antioxidant, and Antimicrobial Activities.

Wedelia chinensis is a folk medicine used in many Asian countries to treat various ailments. Earlier investigations reported that the petroleum ether extract of the plant has potential biological activity, but the compounds responsible for activity are not yet completely known. Therefore, the current work was designed to isolate and characterize the compounds from the petroleum ether extract and to study their bioactivities. Four compounds including two diterepenes (-) kaur-16α-hydroxy-19-oic acid (1) and (-) kaur-16-en-19-oic acid (2), and two steroids ß-sitosterol (3), and cholesta-5,23-dien-3-ol (4) were isolated and characterized. Among the compounds, the diterpenes were found to have more biological activities than the steroidal compounds. Compound 1 showed the highest cytotoxicity with LC50 of 12.42 ± 0.87 µg/mL. Likewise, it possesses good antioxidant activity in terms of reducing power. On the contrary, compound 2 exerted the highest antiacetylcholinesterase and antibutyrylcholinesterase activity. Both the diterpenes showed almost similar antibacterial and antifungal activity. The identification of diterpenoid and steroid compounds with multifunctional activities suggests that W. chinensis may serve as an important source of bioactive compounds which should be further investigated in animal model for therapeutic potential in the treatment of different chronic diseases.

Stephania japonica Ameliorates Scopolamine-Induced Memory Impairment in Mice through Inhibition of Acetylcholinesterase and Oxidative Stress.

Alzheimer's disease (AD) is a progressive neurological disorder characterized by loss of memory and cognition. Stephania japonica is being used as traditional medicine in the treatment of different neurological problems. In this study, we evaluated the anticholinesterase and antioxidant activities of the crude methanol extract of S. japonica and its fractions in vitro and the neuroprotective effect of the most active fraction in the scopolamine-induced mouse model of memory impairment. Among the crude extract and its fractions, chloroform fraction exerted strong inhibition of acetylcholinesterase and butyrylcholinesterase enzymes with IC50 values of 40.06 and 18.78 µg/mL, respectively. Similarly, the chloroform fraction exhibited potent antioxidant activity and effectively inhibited the peroxidation of brain lipid in vitro. The phytochemical profile revealed the high content of polyphenolics and alkaloids in the chloroform fraction. Pearson's correlation studies showed a significant association of anticholinesterase and antioxidant activity with alkaloid and phenolic contents. Kinetic analysis showed that the chloroform fraction exhibited a noncompetitive type of inhibition. In experimental mice, the chloroform fraction restored the impaired learning and memory induced by scopolamine as evidenced by a significant decrease in latency time and increase of quadrant time in probe trial in Morris water maze task. The chloroform fraction also significantly reduced the activity of acetylcholinesterase and oxidative stress in mice. Our results suggest that the chloroform fraction of S. japonica may represent a potential candidate for the prevention and treatment of AD.

Identification of Polyphenolics from Loranthus globosus as Potential Inhibitors of Cholinesterase and Oxidative Stress for Alzheimer's Disease Treatment.

Mistletoes are considered to be the potential medicinal herbs due to their rich traditional uses. Loranthus globosus is a Bangladeshi mango mistletoe that has been reported as folk medicine for various ailments and diseases. In an attempt to explore its effectiveness in Alzheimer's disease (AD), we investigated the antioxidant and acetylcholinesterase inhibitory activity of L. globosus. We report that the crude methanol extract (CME) of the plant contains a good amount of polyphenolics and possesses antioxidant and cholinesterase inhibitory activity. Fractionation of CME with solvents of varying polarity revealed the highest activity and polyphenolic content in the ethylacetate fraction (EAF). Correlation analysis revealed a significant (P < 0.05) association of polyphenolics with the antioxidant and cholinesterase inhibitory properties. Using column chromatography with diaion resin, the polyphenolics (EAF-PP) were isolated from the EAF that displayed the potent antioxidant and cholinesterase inhibitory activities. Kinetic analysis showed that EAF-PP exhibited a competitive type of inhibition. A total of thirty-six compounds including catechin and its different derivatives were identified in the EAF-PP by LC/MS analysis. Bioactivity-guided separation approach afforded the isolation of the two major active compounds catechin and catechin dimer from the EAF-PP. Hence, EAF-PP represents a potential source of antioxidants and cholinesterase inhibitors, which can be used in the management of AD.

Evaluation of cholinesterase inhibitory and antioxidant activity of Wedelia chinensis and isolation of apigenin as an active compound.

BACKGROUND: Wedelia chinensis has been reported as a folk medicine for the treatment of different diseases including neurodegenerative disease. Although the plant has been studied well for diverse biological activities, the effect of this plant in neurological disorder is largely unknown. The present study was undertaken to evaluate the cholinesterase inhibitory and antioxidant potential of W. chinensis. METHODS: The extract and fractions of the plant were evaluated for acetylcholinesterase and butyrylcholinesterase inhibitory activity by modified Ellman method. The antioxidant activity was assessed in several in vitro models/assays such as reducing power, total antioxidant capacity, total phenolic and flavonoid content, scavenging of 2,2'-diphenyl-1-picrylhydrazyl (DPPH) free radical and hydroxyl radical, and inhibition of brain lipid peroxidation. Chromatographic and spectroscopic methods were used to isolate and identify the active compound from the extract. RESULTS: Among the fractions, aqueous fraction (AQF) and ethylacetate fraction (EAF) exhibited high inhibition against acetylcholinesterase (IC50: 40.02 ± 0.16 µg/ml and 57.76 ± 0.37 µg/ml) and butyrylcholinesterase (IC50: 31.79 ± 0.18 µg/ml and 48.41 ± 0.05 µg/ml). Similarly, the EAF and AQF had high content of phenolics and flavonoids and possess strong antioxidant activity in several antioxidant assays including DPPH and hydroxyl radical scavenging, reducing power and total antioxidant activity. They effectively inhibited the peroxidation of brain lipid in vitro with IC50 values of 45.20 ± 0.10 µg/ml and 25.53 ± 0.04 µg/ml, respectively. A significant correlation was observed between total flavonoids and antioxidant and cholinesterase inhibitory activity. Activity guided chromatographic separation led to the isolation of a major active compound from the EAF and its structure was elucidated as apigenin by spectral analysis. CONCLUSIONS: The potential ability of W. chinensis to inhibit the cholinesterase activity and peroxidation of lipids suggest that the plant might be useful for the management of AD.

Phytochemical Analysis and Cholinesterase Inhibitory and Antioxidant Activities of Enhydra fluctuans Relevant in the Management of Alzheimer's Disease.

Enhydra fluctuans, a popular vegetable in Bangladesh, is used in folk medicine to treat diseases of the nervous system. The objective of this study was to investigate the phytochemical profile and cholinesterase inhibitory and antioxidant potential of the extracts of E. fluctuans. Among the four tested extracts, the chloroform extract was found to exert the highest inhibition against both the acetylcholinesterase and butyrylcholinesterase enzymes with the IC50 (concentration required for 50% inhibition) values of 83.90 µg/mL and 48.14 µg/mL, respectively. Likewise, the chloroform extract showed the highest radical scavenging activity and reducing power. In DPPH radical scavenging assay, the IC50 value was found to be 113.27 µg/mL, and in reducing power assay, the absorbance was found to be 1.916 at a concentration of 50 µg/mL. Phytochemical analyses revealed that the chloroform extract contained 19.16 mg gallic acid equivalent (GAE)/g extract of phenolics and 41.84 mg catechin equivalent (CE)/g extract of flavonoids, which appeared to be the highest among the extracts. A significant correlation was observed between phenolic content and butyrylcholinesterase inhibition and antioxidant activity, while a moderate correlation was seen between flavonoid content and cholinesterase inhibition and antioxidant activity. These findings suggest that E. fluctuans is a natural source of cholinesterase inhibitors and antioxidants, which could be utilized as functional foods for Alzheimer's disease management.