Factors regulating nitric oxide production in spontaneously hypertensive rats treated with piper sarmentosum aqueous extract

Introduction: High blood pressure is a major risk factor for cardiovascular diseases which is one of the leading causes of death worldwide. Piper sarmentosum (PS) leaves have been widely used in traditional medicine and it has been proven for its antihypertensive and antioxidant effects. This study aims to evaluate the antihypertensive potential of PS aqueous extract (PSAE) and to investigate the factors modulating nitric oxide (NO) production through its anti-oxidant activities. Materials and Methods: PS leaves were extracted with distilled water and freezedried. The PSAE was examined to quantify their antioxidant activities through DPPH and FRAP test. It is also screened for total phenolic and flavonoids content. The antihypertensive effect of PSAE in SHR was evaluated using four different groups (n=6); C group (negative control), K group (PSAE 500mg/kg), P group (3 mg/kg perindopril) and M group (PSAE + 1.5 mg/kg perindopril). PSAE and other treatment were given via oral gavage for 28 consecutive days. The blood pressure and heart rate were determined using the non-invasive blood pressure monitoring (NIBPM) tail cuff technique and recorded weekly for four weeks. SHR’s blood was collected for the determination of serum NO level using Griess assay. Asymmetric dimethylarginine (ADMA) and arginine levels were determined using HPLC. Results: PSAE shows good in-vitro antioxidant activities with significant reduction of BP and decreased serum ADMA level. Conclusion: PSAE enhances the clearance of ADMA that maintains arginine level, thus increasing the serum NO level, which ameliorate the blood pressure of SHR

Piper sarmentosum leaves aqueous extract attenuates vascular endothelial dysfunction in spontaneously hypertensive rats

Piper sarmentosum is a tropical plant in Southeast Asia known for its traditional use in curing various ailments including hypertension. Previous research works have provided evidence for the herb’s antihypertensive property. However, the exact mechanisms involved are still in question. The present study investigated the effects of Piper sarmentosum leaves aqueous extract (PSAE) treatment on vascular endothelin system in spontaneously hypertensive rats (SHRs). Four groups of SHRs were treated for 28 consecutive days, with negative and positive control groups receiving distilled water and 3 mg/kg perindopril, respectively. Another two groups are the treatment groups, which received PSAE and combination of 1.5 mg/kg perindopril and PSAE. Weekly measurements of blood pressure showed that PSAE significantly reduced the systolic, diastolic, and mean arterial pressures () of the rats. PSAE also increased mesenteric artery nitric oxide (NO) level () and reduced endothelin-1 (ET-1) level () in the treatment groups. Our results demonstrate that oral administration of PSAE reduced blood pressure in SHRs by reducing the ET-1 level while increasing NO production

The antihypertensive efficacy of Piper sarmentosum aqueous extract as compared to perindopril in spontaneously hypertensive rats

Aims/Objective: One of the impediments in overcoming hypertension is treatment failure caused by patient compliance in conventional medicine. Herbal remedies receive less defiance, and thus have been studied considerably. This study aimed to evaluate the efficacy of Piper sarmentosum aqueous extract (PSAE) in reducing blood pressure via endothelial dysfunction amelioration as compared to angiotensin-converting-enzyme (ACE) inhibitor, Perindopril. Methods: Blood pressure indices, level of mesenteric artery nitric oxide (NO) and endothelin1 (ET-1) were studied in four different groups (n=6) of spontaneously hypertensive rats (SHR) i.e. i) received distilled water, ii) 3 mg/kg Perindopril, iii) 500 mg/kg PSAE, and iv) a combination of 1.5 mg/kg Perindopril and 500 mg/kg PSAE. The rats were treated for 28 consecutive days, and blood pressure was measured weekly. NO and ET-1 level were analysed at the end of treatment period, after the rats were humanely sacrificed. Results: All three groups that received treatments have significantly lower systolic, diastolic, and mean arterial pressure (P<0.05), as well as higher NO level (P<0.05), and lower ET-1 level (P<0.05) as compared to the group receiving distilled water. However, rats that received Perindopril have the lowest systolic, diastolic, and mean arterial pressure, highest NO level, and lowest ET-1 level, followed by SHR treated by combined therapy and PSAE. Conclusion: Use of PSAE alone in once daily (OD) dose does not demonstrate better outcome than use of conventional Perindopril therapy in hypertensive subject. Further trials are imperative to fully establish the efficacy, tolerability, and possible adjuvant capacity of this potentially therapeutic agent