Isolation of Major Phenolic Compounds from the Extracts of Prunella L. Species Grown in Turkey and Their Antioxidant and Cytotoxic Activities

Vulgarisin-type diterpenoids from self-heal (Prunella vulgaris) and their neuroprotective effects against ischemia/reperfusion (I/R) via a mitochondria-related pathway

Self-heal (Prunella vulgaris L.) is a perennial edible plant that is widely distributed across the world and is traditionally consumed as a food additive in soft drink beverages. In this study, to explore the functional components of P. vulgaris, an investigation of its ethanol extracts has been conducted by our group. As a result, twelve (1-12) vulgarisin-type diterpenoids with a special 5/6/4/5-fused ring skeleton, including six new ones (1-6), were obtained. Their structures including the absolute configuration were elucidated based on comprehensive spectroscopic evidence, ECD calculations, as well as single-crystal X-ray diffraction analyses. All the isolates were tested for neuroprotective effects against ischemia/reperfusion (I/R) on primary neuron cells through the oxygen and glucose deprivation and reperfusion (OGD/R) induced injury model. The results showed that all twelve vulgarisin-type diterpenoids possess promising neuroprotective activity at a concentration of 10 μM. Among them, compound 3 can significantly suppress cell apoptosis by regulating Bax/Bcl-2 protein expression and inhibiting cleaved caspase-3 and caspase-9 expression with a western blotting assay. Further research revealed that compound 3 could improve mitochondrial function by inhibiting mitochondrial cytochrome c release, reducing ROS levels, and maintaining the membrane potential. This work firstly reports vulgarisin-type diterpenoids possessing neuroprotective activity. These findings also suggest that daily consumption of P. vulgaris might prevent cerebral disorders via a mitochondria-related pathway.

Effect of ultrasonic treatment on total phenolic extraction from Lavandula pubescens and its application in palm olein oil industry

The aims of the current study were to evaluate the best technique for total phenolic extraction from Lavandula pubescens (Lp) and its application in vegetable oil industries as alternatives of synthetic food additives (TBHQ and BHT). To achieve these aims, three techniques of extraction were used: ultrasonic-microwave (40 kHz, 50 W, microwave power 480 W, 5 min), ultrasonic-homogenizer (20 kHz, 150 W, 5 min) and conventional maceration as a control. By using the Folin-Ciocalteu method, the total phenolic contents (TPC) (mg gallic acid equivalent/g dry matter) were found to be 253.87, 216.96 and 203.41 for ultrasonic-microwave extract, ultrasonic-homogenizer extract and maceration extract, respectively. The ultrasonic-microwave extract achieved the higher scavenger effect of DPPH (90.53%) with EC50 (19.54 μg/mL), and higher inhibition of β-carotene/linoleate emulsion deterioration (94.44%) with IC50 (30.62 μg/mL). The activity of the ultrasonic-microwave treatment could prolong the induction period (18.82 h) and oxidative stability index (1.67) of fresh refined, bleached and deodorized palm olein oil (RBDPOo) according to Rancimat assay. There was an important synergist effect between citric acid and Lp extracts in improving the oxidative stability of fresh RBDPOo. The results of this work also showed that the ultrasonic-microwave assisted extract was the most effective against Gram-positive and Gram-negative strains that were assessed in this study. The uses of ultrasonic-microwave could induce the acoustic cavitation and rupture of plant cells, and this facilitates the flow of solvent into the plant cells and enhances the desorption from the matrix of solid samples, and thus would enhance the efficiency of extraction based on cavitation phenomenon.

Phytochemistry and pharmacological activities of the genus Prunella

Prunella is a genus of perennial herbaceous plants in the Labiatae family. There are approximately 15 species worldwide, distributed widely in the temperate regions and tropical mountains of Europe and Asia. In the genus Prunella, P. vulgaris is the most studied, following a several thousand-year history as a traditional antipyretic and antidotal Chinese herb. Furthermore, since ancient times, P. vulgaris has been widely used as a cool tea ingredient and consumed as a vegetable. The genus Prunella contains triterpenoids and their saponins, phenolic acids, sterols and associated glycosides, flavonoids, organic acids, volatile oil and saccharides. Modern pharmacological studies have revealed that Prunella possess antiviral, antibacterial, anti-inflammatory, immunoregulatory, anti-oxidative, anti-tumor, antihypertensive and hypoglycemic functions. The active components related to these functions are mainly triterpenoids, phenolic acids, flavonoids and polysaccharides. This review mainly summarizes recent advances in traditional usage, chemical components and pharmacological functions.

Antioxidant and DNA damage protection potentials of selected phenolic acids

In this study, ten different phenolic acids (caffeic, chlorogenic, cinnamic, ferulic, gallic, p-hydroxybenzoic, protocatechuic, rosmarinic, syringic, and vanillic acids) were evaluated for their antioxidant and DNA damage protection potentials. Antioxidant activity was evaluated by using four different test systems named as β-carotene bleaching, DPPH free radical scavenging, reducing power and chelating effect. In all test systems, rosmarinic acid showed the maximum activity potential, while protocatechuic acid was determined as the weakest antioxidant in β-carotene bleaching, DPPH free radical scavenging, and chelating effect assays. Phenolic acids were also screened for their protective effects on pBR322 plasmid DNA against the mutagenic and toxic effects of UV and H2O2. Ferulic acid was found as the most active phytochemical among the others. Even at the lowest concentration value (0.002 mg/ml), ferulic acid protected all of the bands in the presence of H2O2 and UV. It is followed by caffeic, rosmarinic, and vanillic acids. On the other hand, cinnamic acid (at 0.002 mg/ml), gallic acid (at 0.002 mg/ml), p-hydroxybenzoic acid (at 0.002 and 0.004 mg/ml), and protocatechuic acid (at 0.002 and 0.004 mg/ml) could not protect plasmid DNA.