Hazrulrizawati Abd Hamid

Indole Alkaloids from Plants as Potential Leads for Antidepressant Drugs: A Mini Review

Depression is the most common illness observed in the elderly, adults, and children. Antidepressants prescribed are usually synthetic drugs and these can sometimes cause a wide range of unpleasant side effects. Current research is focussed on natural products from plants as they are a rich source of potent new drug leads. Besides Hypericum perforatum (St. John’s wort), the plants studied include Passiflora incarnata L. (passion flower), Mitragyna speciosa (kratom), Piper methysticum G. Forst (kava) and Valeriana officinalis L. Harman, harmol, harmine, harmalol and harmaline are indole alkaloids isolated from P. incarnata, while mitragynine is isolated from M. speciosa. The structure of isolated compounds from P. methysticum G. Forst and V. officinalis L. contains an indole moiety. The indole moiety is related to the neurotransmitter serotonin which is widely implicated for brain function and cognition as the endogenous receptor agonist. An imbalance in serotonin levels may influence mood in a way that leads to depression. The moiety is present in a number of antidepressants already on the market. Hence, the objective of this review is to discuss bioactive compounds containing the indole moiety from plants that can serve as potent antidepressants.

UPLC-QTOF/MS-based phenolic profiling of Melastomaceae, their antioxidant activity and cytotoxic effects against human breast cancer cell MDA-MB-231

Eleven compounds were identified during profiling of polyphenols by UPLC-QTOF/MS. In abundance was quercetin-3-O-α-l-arabinofuranoside in M. malabathricum ethanolic leaves extract while 6-hydroxykaempferol-3-O-glucoside was present in the leaves extract of M. decenfidum (its rare variety). TPC and TFC were significantly higher in M. decemfidum extract than M. malabathricum extract. During DPPH, FRAF and β-carotene bleaching assays, M. decemfidum extract exhibited greater antioxidant activity compared to M. malabathricum extract. Effect of M. malabathricum and M. decemfidum extracts on viability of MDA-MB-231 cell at concentrations 6.25-100 μg/mL were evaluated for 24, 48 and 72 h. After 48 and 72 h treatment, M. malabathricum and M. decemfidum leaves extracts exhibited significant activity in inhibiting MDA-MB-231 cancer cell line with M. malabathricum extract being more cytotoxic. M. malabathricum and M. imbricatum serves as potential daily dietary source of natural phenolics and to improve chemotherapeutic effectiveness.

Comparative structural analysis of fruit and stem bromelain from Ananas comosus

Cysteine proteases in pineapple (Ananas comosus) plants are phytotherapeutical agents that demonstrate anti-edematous, anti-inflammatory, anti-thrombotic and fibrinolytic activities. Bromelain has been identified as an active component and as a major protease of A. comosus. Bromelain has gained wide acceptance and compliance as a phytotherapeutical drug. The proteolytic fraction of pineapple stem is termed stem bromelain, while the one presents in the fruit is known as fruit bromelain. The amino acid sequence and domain analysis of the fruit and stem bromelains demonstrated several differences and similarities of these cysteine protease family members. In addition, analysis of the modelled fruit (BAA21848) and stem (CAA08861) bromelains revealed the presence of unique properties of the predicted structures. Sequence analysis and structural prediction of stem and fruit bromelains of A. comosus along with the comparison of both structures provides a new insight on their distinct properties for industrial application.

Poly(vinyl alcohol) electrospun nanofibers containing antimicrobial Rhodomyrtus tomentosa extract

Electrospun nanofibers were prepared from Rhodomyrtus tomentosa extract and poly(vinyl alcohol). The antimicrobial effect was assessed against two Gram-negative bacterial strains (Escherichia coli, Pseudomonas aeruginosa) and two Gram-positive bacterial strains (Bacillus subtilis, Enterococcus faecalis) by paper disc diffusion method. Ethyl acetate extract of R. tomentosa was selected for fabrication of nanofibers because it shows the most active antimicrobial activity with zone of inhibition ranging from 9.33 ± 0.21 to 13.67 ± 0.32 mm. The presence of high abundance of myricetin and rhodomyrtone might contribute to the antibiotic activity against all tested bacterial strains. The average diameter of the R. tomentosa extract/poly(vinyl alcohol) nanofibers increased from 120.4 to 214.8 nm with increasing concentration of R. tomentosa extract from 0.5% to 2.5%. The antimicrobial activity of R. tomentosa extract/poly(vinyl alcohol) nanofibers was relatively higher at concentration of the extract (1.5% and 2.5%) against all test organisms with a clear zone of inhibition 7–12 mm. The results demonstrated that R. tomentosa extract/poly(vinyl alcohol) electrospun nanofibers are an interesting platform for delivery of bioactive compounds as wound dressing or other strategies for combating bacterial infections.

Dihydroactinidiolide from thermal degradation of β-carotene

ABSTRACT The formation of dihydroactinidiolide by thermal degradation of β-carotene was studied. A comparison of yields of dihydroactinidiolide in commercial β-carotene and β-carotene derived from crude palm oil was investigated. Thermal degradation of commercial β-carotene promoted the formation of dihydroactinidiolide with the highest yield, 61.21%. Thermal degradation of recovered β-carotene yielded 29.23% of dihydroactinidiolide. The lower recovery of β-carotene was due to the mixture of compounds in the extract. Further investigation indicated some other useful aroma compounds formed from this thermal degradation were β-ionone, 3-oxo-β-ionone, and β-cyclocitral.The outcome provided wide opportunities in utilizing crude palm oil as natural source of β-carotene to produce aroma compound.