Effect of Enalapril Plus Folic Acid on Blood Pressure and Glycometabolism

Inclusion Criteria: 1. Age≥18 years and less than 75 years 2. Essential hypertension patients 3. Sedentary systolic blood pressure≥140mmHg and less than 180mmHg, and/or sedentary diastolic blood pressure≥90mmHg and less than 110mmHg 4. Reproductive women agree to take a reliable contraception measure during the trial 5. Written informed consent Exclusion Criteria: 1. Pregnant women 2. Women within lactateion period 3. Hypersensitive to Angiotensin-Converting Enzyme Inhibitor (ACEI) or folic acid 4. Easily hypersensitiveness 5. Diagnosed secondum hypertension or skeptical secondum hypertension 6. Severe hypertension (sedentary systolic blood pressure greater than or equal to 180 mmHg and/or sedentary diastoleic blood pressure greater than or equal to 110 mmHg) 7. Severe diseases: * Cardiovascular system * Diagnosed cardia insufficiency (New York Health Association \[NYHA\] III level and higher) * Hypertrophic obstructive cardiomyopathy (HOCM) * Clinical significantly Valvular Disease of the Heart (VDH) * Acute coronary syndrome or coronary artery interventional therapy or coronary artery bypass graft within three months * Severe arrhythmia such as atrial flutter, atrial fibrillation, ventricular arrhythmia above Lown ?, atrioventricular block above II level, etc. * Alimentary system disorders * Active virus hepatitis * Any of alanine aminotransferase (ALT), aspartate aminotransferase (AST), galactosylhydroxylysyl glucosyltransferase (GGT), alkaline phosphatase (ALP), total bilirubin (TBIL), Direct Bilirubin (DB) was above 2 times of it's normal value upper limit, albumin (ALB) greater than 30 g/L * Stomach bulk resect and gastrojejunostomy, stomach intestine malabsorption Urinary system: * Serum creatinine greater than or equal to 200 mmol/L * Diagnosed stenosis of renal artery, solitary kidney * Renal transplantation Endocrine system: * Type 1 diabetes mellitus or uncontrolled type 2 diabetes mellitus (fasting glucose greater than or equal to 11.1 mmol/L) * Diagnosed and uncontrolled hyperthyrosis Respiratory system: * Chronic cough nervous or psyche system: * Transient Ischemia Attach (TIA) or stoke within 3 months * Severe peripheral nerve or vegetative nerve functional disturbance * Psyche or nervous system dysfunction * Drugs or alcohol dependence Others: * Malignant tumor * Malnutrition, haematogenesis dysfunction, etc. 8. Taking other antihypertensive drugs 9. Taking folic acid or other Vitamin B groups Primary Outcome Measures: 1. Blood pressure of study participants was measured at baseline, 2th week, 4th week, 6th week and at the end of trial 2. Subjects' plasma total homocysteine concentration were measured at baseline, 4th week and at 8th week. Secondary Outcome Measures: 1. Participants' living habit and life style were collected at baseline with the original questionnaires. 2. A follow up questionnaire was sent out at 2th week, 4th week, 6th week and at the end of the trial.