Serpentina is a small shrub with whorled branches and milky sap. Leaves are opposite, entire, oblong-elliptic, up to 30 centimeters long. Flowers are white, clustered in axillary cymes, with slender corolla tube and 5 spreading lobes. Fruit is a small drupe.
- Introduced to the Philippines.
- Indigenous to India and tropical Asia.
- Reported in the Himalayas, Assam, Java, and the Malaya peninsula.
- Yields bioactive constituents: yohimbine, reserpine, ajmaline, deserpidine, rescinnamine, serpentinine.
- Roots have yielded two alkaloids (1% of the dried root), a lot of resin and starch.
- Study yielded phytosterols, oleic acid, and unsaturated alcohols, and five alkaloids classified in two groups: three in the ajmaline group, white crystalline, weak bases, ajmaline, ajmaliine, and ajmalicine; and two in the serpentine group, yellow crystalline stronger bases, serpentine and serpentinine.
- The principal active constituent is the alkaloid reserpine.
- Bitter, cool.
- Considered hypotensive, neuroleptic, sympatholytic.
- Febrifuge, antitussive, diuretic.
- In Siddha medicine, considered antihypertensive, styptic, nervine-tonic and abortifacient.
- No reported folkloric medicinal use in the Philippines.
- A medicinal plant of antiquity. Used for millenia inn India. Used to counter the effects of poisoned arrow. Ghandi reported used it as a tranquilizer.
- Used as febrifuge, as stimulant to uterine contractions, for insomnia and insanity.
- Used for high blood pressure.
- For millenia, used as antidote to stings and bites of insects and poisonous reptiles.
- Used in Ayurveda, Unani and folk medicine systems for reducing blood pressure, for its CNS depressant effect, and as hypnotic.
- Ingredient to an Ayurvedic herbal mixture once used in the treatment of schizophrenia.
- In India, referred to as the "insanity herb," used to treat mental disorders, i.e., anxiety, paranoia, nervousness.
- In Siddha medicine, root power given with equal amounts of Triphala powder twice daily is used for hypertension and associated headache and giddiness. Root powder given for amenorrhea, oligomenorrhea and dysmenorrhea-like abnormalities. For snake bites and scorpion bites, root powder mixed with Piper cubeba and salt applied externally to the bite as well as taken internally. For hysteria in women and epilepsy, root powder is mixed with equal amounts of powder of Nardostachys jatamanji.
- Wood: Used for woodcarving and lathe work.
• Pharmacologic Activities: Studies on the root have shown: (1) Action on the vaso-motor center, with generalized vasodilation and lowering of blood pressure. (2) Depressant action on the nervous system (3) Sedative action on the gastric mucosa (4) Stimulation of the bronchial musculature.
• Hypotensive: Study showed R. serpentina proved capable of lowering both systolic and diastolic blood pressure. (3)
• Mechanisms of Hypotensive Action of Reserpine: Studies on the alkaloid reports: (1) the marked hypotensive effect was in part due to depression of CNS mechanisms. It was less marked in decerebrate animals. (2) Effect was, in part, a result of a direct inhibitory effect on the musculature of the blood vessels. (3) There was a fall i cardiac output of the isolated heart. (4) Subsequent studies have suggested the effect mediated solely via central nervous mechanisms. (4)
• Strictosidine Synthase: STR1 from R. serpentina is of primary importance for the biosynthetic pathway of the indole alkaloid ajmaline. STR1 catalyzes a Pictet-Spengler-type reaction and represents a novel six-bladed ß-propeller fold in plant proteins. Mutagenesis experiments demonstrate the essential role of Glu-309 in catalysis. (5)
• Psychoactive: Considered a theoretical psychoactive due to the yohimbane-type alkaloids (corynanthine, isorauhimbine, and yohimbine.
• Side Effects / Depression: Crude and purified derivatives are considered free of serious toxic reactions. Mild side effects are frequent, consisting of nasal stuffiness, fatigue, weight gain, decreased initiative, drowsiness, nightmares, and diarrhea. Symptoms can be relieved by reducing the dosage without sacrificing its hypotensive effect. In large doses, depression occurs with significant frequency. (6)
• Hypolipidemic: Study showed root powder of R. serpentina has hypotriglyceridemic and hypocholesterolemic effects with no detectable side effects on liver and cardiac functions. (7)
• Serpasil / Cardiovascular and Respiratory Effects: Serpasil, a crystalline alkaloid obtained from Rauwolfia serpentina, produced a gradual persistent blood pressure and respiratory depression when administered intravenously to barbitalized dogs. No significant blood pressure drop occurred in five unanesthetized dogs with serpasil administration. Serpasil produces a central inhibition of the sympathetic nervous system, possibly through specific hypothalamic depression. (9)
• Antibacterial: Study evaluated the antibacterial effect of RS aqueous and ethanol extracts, with Norfloxacin as control drug. Results showed the ethanol extract exhibited greater antibacterial activity than the aqueous extract against Staphylococcus aureus. (10)
• Corrosion Inhibition: Study evaluated an alkaloid extract of R. serpentina as corrosion inhibitor for mild steel in 1 M HCl and H2SO4. Results showed inhibition of corrosion in both acids through absorption process and formation of a protective layer over the mild steel surface. (11)
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