The Effects of 4-Hydroxybenzoic Acid Identified from Bamboo (Dendrocalamus asper) Shoots on Kv1.4 Channel

Abstract

Background: Bamboo shoot has been used as a treatment for epilepsy in traditional Chinese medicine for generations to treat neuronal disorders such as convulsive, dizziness and headaches. 4-hydroxybenzoic acid (4-hba) is a non-flavonoid phenol found abundantly in Dendrocalamus asper shoots (bamboo), fruits (strawberries and apples) and flowers. Kv1.4 is a rapidly inactivating Shaker-related member of the voltage-gated potassium channels with two inactivation mechanisms; the fast N-type and slow C-type. It plays vital roles in repolarisation, hyperpolarisation and signaling the restoration of resting membrane potential through the regulation of the movement of K + across the cellular membrane. Methods: Chemical compounds from Dendrocalamus asper bamboo shoots were purified and identified as major palmitic acids mixed with other minor fatty acids, palmitic acid, 4-hydroxybenzaldehyde, lauric acid, 4-hydroxybenzoic acid and cholest-4-ene-3-one. The response of synthetic 4-hydroxybenzoic acid was tested on Kv1.4 potassium channel which was injected into viable oocytes that was extracted from Xenopus laevis. The current were detected by the two-microelectrode voltage clamp, holding potential starting from −80 mV with 20 mV stepup until +80 mV. Readings of treatments with 0.1% DMSO, 4-hba concentrations and K channel blockers were taken at +60 mV. The ratio of tail/peak amplitude is the index of the activity of the Kv1.4 channels with n ≥ 6 (number of oocytes tested). The decreases of the ratios of five different concentrations (1 µM, 10 µM, 100 µM, 1 mM and 2.5 mM) were compared with 0.1% DMSO as the control. 4-hydroxybenzoic acid (4-hba) is a nonflavonoid phenolic compound from benzoic acid derivatives (BADs) along with other biocompounds such as salicylic acid, gallic acid and vanilic acid (18). It constitutes of aromatic benzene ring, hydroxyl substituent and functional derivative that influences the mechanisms, biological activities and properties (19). It is able to pass through blood vessels, blood brain barriers (BBB) and cerebrospinal fluid (CSF) due to its low molecular weight (138.12074 Da) (20). As to date, there are not many toxicity studies of this compound on human however, it has been recorded to be slightly irritating to skin and eyes and the maximum bodily intake is estimated to be 0.067 mg/kg/day (for body weight; 70 kg) (21). Other than being used in pharmaceuticals and cosmetic products, 4-hba has been reported to have antifungal, antialgal, antimutagenic, antisickling properties, extrogenic activity and used as trapping agent on hydroxyl radical generation using cerebral ischemia and reperfusion (22).Voltage-gated potassium channels play essential role in restoring the membrane potential and signaling subsequent action potential during neuronal regulation. It is the most abundant and diverse ionic channel identified in the human body with more than 40 types encoded by more than 70 genes and classified into 12 subfamilies (Kv1-Kv12) (23). Kv1 family (Shaker) is mostly distributed around b...

Phytotherapeutic options for the treatment of epilepsy: pharmacology, targets, and mechanism of action

“…In addition, no cytotoxic activities have been reported. Jingli and colleagues investigated the effect of the 4hba on the Kv, and they reported that 4hba enhanced the activity of the potassium channels family Kv1.4 and contributed to the reduction of membrane excitation (Zhang et al, 2018). Therefore, from these results, we can conclude that the 4hba compound could help in controlling the depolarization and excitation of neurons in seizures and, therefore, can be a potent agent against epilepsy in the future.…”

Chemical and Biological Characterize of Dendrocalamus asper (Schult.) Backer

“…The biological activity of Bamboo revealed to phyto-constituents like phenolics, minerals and water-soluble vitamins [14][15][16][17] . From the phytochemical standpoint, bamboo was approved to be a rich source of phenols and phytosterols [18][19][20]. Dendrocalamus asper (Schult.)…”