Gotu Kola (Centella asiatica)

Overview

Gotu Kola (Centella asiatica) is a low‑lying, herbaceous plant native to tropical Asia and the Pacific. Its aerial parts have been used for centuries as a culinary herb and in traditional medicine, primarily to support skin health, cognition, and circulatory function. Modern research focuses on its rich array of triterpenoid saponins, which appear to mediate many of its therapeutic actions.

Benefits

Cognitive support: Randomized trials report modest improvements in memory and attention in healthy adults and in mild cognitive impairment, likely linked to enhanced cerebral blood flow and neuro‑protective signaling.
Skin and wound healing: Topical and oral use accelerate collagen synthesis, reduce scar formation, and improve barrier function in burn, ulcer, and postoperative models.
Vascular health: Clinical data show reduced venous hypertension, decreased capillary permeability, and modest reductions in systolic blood pressure in individuals with chronic venous insufficiency.
Anxiety & mood: Small‑scale trials suggest anxiolytic effects via modulation of GABAergic activity and reduced cortisol.
Metabolic effects: Preliminary human studies indicate modest improvements in insulin sensitivity and lipid profiles, especially in overweight adults, though larger trials are needed.

How It Works

Principal bioactives: Asiaticoside, madecassic acid, and their aglycones (asiatic acid, madecassic acid) are triterpenoid saponins that penetrate the skin and cross the blood‑brain barrier.
PI-3K/Akt pathway: They activate the phosphatidyl‑inositol‑3‑kinase (PI‑3K)/Akt pathway, enhancing collagen‑type I synthesis and fibroblast proliferation, which underlies wound-healing effects.
Neuronal tissue: These compounds elevate brain‑derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF), promoting neurogenesis and angiogenesis.
Anti-inflammatory and antioxidant benefits: The compounds also inhibit NF‑κB and oxidative-stress pathways (e.g., reducing ROS and lipid peroxidation).
Anxiolytic activity: They modulate GABA‑A receptors and reduce cortisol, contributing to anxiolytic activity.
Combinatorial modulation: The combinatorial modulation of these pathways explains the broad, yet mechanistically coherent, health effects observed.

Dosage

Standardized oral extract (10 %–20 % triterpenoids): 300–600 mg per day, divided into 1–2 doses, taken with food to improve absorption.
Higher‑strength extracts (≥30 % triterpenoids): 150–300 mg per day, typically taken once in the morning to avoid potential mild sedation later.
Topical preparations: 0.5–2 % (w/w) cream or gel applied 2–3 times daily to clean, dry skin; a 4‑week trial is recommended before longer use.
Special cases:
- For cognitive enhancement, 300 mg of 10 % triterpene extract in the morning is common.
- For venous insufficiency, a slightly higher dose (450–600 mg) divided morning and evening is supported by clinical trials.
Adjustments: Adjust doses downward for elderly or renal‑impaired individuals.

Safety & Side Effects

General tolerance: Gotu Kola is generally well‑tolerated at recommended doses.
Side effects: Reported side‑effects are mild: gastrointestinal discomfort, nausea, or headache in <5 % of users.
Hepatotoxicity: Rare hepatotoxicity has been reported with high‑dose, prolonged use (>2 g/day) and in individuals with pre-existing liver disease.
Contraindications:
- Pregnancy (possible uterine stimulation) and lactation (insufficient data).
- Contraindicated in individuals taking CNS depressants (e.g., benzodiazepines) due to additive sedative effects, and antiplatelet/anticoagulant drugs (e.g., warfarin) because of possible platelet inhibition.
Precautions: Persons with renal disease, hepatic impairment, or photosensitivity disorders should use lower doses (≤300 mg/day) and monitor liver function.

Chemistry

Asiatic acid: The principal bioactive, asiatic acid (C₃₀H₄₈O₅; IUPAC: (3S,5R,6R,8S,9R,10R,13R,14R,15S,16R,17R)-3,5,6,8,9,10,13,14,15,16,17‑undecahydro‑2‑(2‑hydroxy‑2‑methyl‑propyl)-17‑(hydroxy‑methyl)‑2‑(2‑hydroxy‑3‑methyl‑but-1‑enyl)‑3,5,6,8,9,10,13,14,15,16,17‑decahydro‑1‑H‑cyclopenta[a]phenanthrene‑3‑carboxylic acid, is a pentacyclic triterpenoid.
Other compounds: The plant also contains madecassic acid, centellosides, flavonoids (e.g., quercetin), and a range of phenolic acids.
Asiatic acid properties: Molecular weight of asiatic acid: 488.71 g·mol⁻¹, with a logP ≈ 3.5, indicating moderate lipophilicity that facilitates membrane penetration.
Saponin glycosides: The saponin glycosides (e.g., asiaticoside) are more polar (logP ≈ −1) and require hydrolysis (by intestinal microbiota or hepatic enzymes) to release the active aglycones.

Sources & Quality

Cultivation: Gotu Kola is cultivated primarily in India, Sri Lanka, Indonesia, and the Philippines, where the climate (high humidity, warm temperatures) supports optimal phytochemical content.
Supplement source: Commercial supplements are typically derived from aerial parts (leaves, stems) harvested at the vegetative stage, then dried and milled.
Extraction methods: Extraction commonly employs ethanol‑water (70 %–80 % ethanol) or super‑critical CO₂ to preserve triterpenoids; water extracts retain higher flavonoid content.
Quality standards: High‑quality extracts are standardized to 10 %–20 % triterpenoid content and certified free of heavy metals (lead, cadmium, arsenic) and pesticide residues.
Quality assurance: Good Manufacturing Practice (GMP) and third‑party testing (e.g., USP, NSF) are essential quality markers, as plant‑derived raw material can vary widely in active‑compound concentration.