Thai traditional herbal formula ‘’Kleeb Bua Daeng (KBD)’’consists of a 1:1:1 ratio (dry weight) of three medicinal plants: Piper nigrum fruit, the aerial part of Centella asiatica and the petals of Nelumbo nucifera. Oral administration of KBD to unpredictable chronic mild stress (UCMS) mice significantly improved their cognitive function caused by chronic mild stress. Daily administration of KBD significantly decreased the serum corticosterone (CORT) and malondialdehyde (MDA) levels but increased the catalase and superoxide dismutase activities in both frontal cortex and hippocampus. The effects of KBD were similar to those caused by oral administration of vitamin E. HPLC analysis of the KBD extract revealed the presence of piperine, madecassoside, asiaticoside, luteolin-7-O-glucoside, rutin, kaempferol-3-glucoside, quercetin, kaempferol and ferulic acid as major constituents.

Treatment of the unpredictable chronic mild stress (UCMS) mice with the ethanol extract of Dipterocarpus alatus leaf attenuated anhedonia (increased sucrose preference) and behavioral despair (decreased immobility time in tail suspension test (TST) and forced swimming test (FST)). The extract not only decreased the elevation of serum corticosterone level and the index of over-activation of the hypothalamic-pituitary-adrenal (HPA) axis, caused by UCMS, but also ameliorated UCMS-induced up-regulation of serum- and glucocorticoid-inducible kinase 1 (SGK1) mRNA expression and down-regulation of cyclic AMP-responsive element binding (CREB) and brain-derived neurotrophic factor (BDNF) mRNAs in frontal cortex and hippocampus. In vitro monoamine oxidase (MAO) inhibition assays showed that the extract exhibited the partial selective inhibition on MAO-A. HPLC analysis of the extract showed the presence of flavonoids (luteolin-7-O-glucoside, kaempferol-3-glucoside, rutin) and phenolic acids (gallic acid, ferulic acid, and caffeic acid) as major constituents.

Wolffia globosa, or watermeal, is an aquatic plant belonging to the Lemnaceae family that is consumed as food and sold in local markets of Thailand. The aim of this study was to quantify selected active compounds and minerals in W. globosa ethanolic extract and evaluate its antioxidant activity. Total phenolic, flavonoid, and anthocyanin contents were analyzed. High-performance liquid chromatography was used for the determination of beta-carotene, ferulic acid, luteolin-7-O-β-D-glucoside, and kaempferol. Mineral contents (iron, potassium, calcium, magnesium, zinc, and sodium) were determined by atomic absorption spectroscopy. Antioxidative activity was evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2-azobis (3-ethylbenzothiazoline-6-sulfonic acid)) radical scavenging assays. The beta-carotene, ferulic acid, luteolin-7-O-β-D-glucoside, and kaempferol contents of the extract were 2.520.10, 1.400.10, 2.420.50, and 1.570.14mg/g extract, respectively. The highest mineral content in the W. globosa extract was magnesium. The wet extract of W. globosa showed higher amounts of all minerals than the dry extract. Freshly prepared and boiled W. globosa extracts showed radical scavenging activity at 1000µg/milliliter with 75.770.93 and 67.100.20 inhibition of DPPH and 70.407.20 and 59.783.16 inhibition of ABTS, respectively. This plant is a promising novel source of natural phytochemical constituents and antioxidants and has potential for development as a plant-based nutraceutical product for the treatment of diseases caused by free radicals.