Evidence-based supplement monograph

Gotu Kola Centella asiatica

Gotu Kola (Centella asiatica) is one of the most extensively studied botanical extracts in traditional Ayurvedic, Chinese, and Southeast Asian medicine. Historically recognized as a rejuvenative herb, modern scientific research has identified a range of bioactive triterpenoids responsible for its effects on connective tissue repair, microcirculation, cognitive function, neuroprotection, wound healing, and vascular health. The primary active compounds include asiaticoside, madecassoside, asiatic acid, and madecassic acid, which influence multiple molecular pathways involved in collagen synthesis, angiogenesis, neuroplasticity, antioxidant defense, and inflammatory regulation. Today, standardized Gotu Kola extracts are widely utilized as supportive supplements for vascular insufficiency, skin health, cognitive performance, healthy aging, and connective tissue integrity.

Triterpene glycosides Wound healing Venous insufficiency Neuroprotection Collagen remodeling Microcirculation Nrf2 and TGF-beta pathways

Active

Active Constituents & Standardization

The primary pharmacologically active compounds are pentacyclic triterpenes:

Triterpene glycosides (saponins): Asiaticoside, madecassoside
Triterpene aglycones: Asiatic acid, madecassic acid

Standardized extracts are usually quantified as total triterpenic fraction (TTF) or specific asiaticoside/madecassoside content. Common potencies include extracts containing 10–40% asiaticosides or a specific TTF concentration (e.g., 95% total triterpenes in research-grade material).

Therapeutic

Therapeutic Dose

Doses vary by indication and extract standardization.

Oral administration (standardized extract, TTF):

Chronic venous insufficiency / microangiopathy: 60–120 mg once or twice daily (total triterpenic fraction)
Cognitive decline / anxiety: 60–120 mg TTF daily, sometimes divided
Wound healing support (post-surgical/trauma): 60–120 mg TTF twice daily
Gastric ulcer adjunct: 60 mg TTF three times daily

Crude powdered leaf (traditional use):

600–1200 mg dried leaf, 2–3 times daily (provides approx. 15–50 mg triterpenes per dose)

Topical (cream/gel):

1% extract (asiaticoside + madecassoside) applied twice daily for wound healing, scars, or keloids.

Note: Doses above 180 mg TTF per day are rarely required and may increase side-effect risk without commensurate benefit. Long-term use ≥6 weeks is often necessary for tissue remodeling effects.

Indications

Indications (Evidence Level)

Indication	Evidence Strength
Wound healing (burns, ulcers, surgical wounds)	Strong (multiple RCTs)
Venous insufficiency / varicose veins	Strong (RCTs vs. placebo)
Keloid & hypertrophic scar prevention	Moderate–strong
Psoriasis (as adjunct)	Moderate (open-label/RCT)
Systemic sclerosis (scleroderma)	Moderate (RCTs)
Mild cognitive impairment & Alzheimer’s disease	Moderate (improved MMSE)
Anxiety disorders	Moderate (anxiolytic effect comparable to benzodiazepines in some studies)
Diabetic microangiopathy & neuropathy	Moderate
Peptic ulcer (adjunct healing)	Moderate
Periodontal healing (topical)	Moderate
Stretch marks (striae) prevention	Mild–moderate
Lymphedema (postmastectomy)	Moderate (volume reduction)
Epilepsy (traditional use)	Preclinical only

Side

Side Effects

Gotu Kola is generally well tolerated. Adverse events are dose-dependent and mostly mild:

Gastrointestinal: Nausea, dyspepsia (rare, <2%)
Neurological: Drowsiness, headache (may diminish with continued use)
Dermatological: Photosensitivity (topical and high-dose oral), contact dermatitis (topical, often due to base not extract)
Metabolic: Hypoglycemia (rare, in susceptible individuals)
Hepatotoxicity: Isolated case reports at very high doses (>1.5 g TTF/day); reversible on discontinuation

Contraindications

Contraindications & Drug Interactions

Contraindications:

Pregnancy: In vitro and animal studies suggest uterine stimulant activity; oral use contraindicated. Topical use on intact skin may be safe, but consensus lacks.
Breastfeeding: No human data; avoid oral use.
Active liver disease or history of drug-induced hepatotoxicity: use only under supervision.
Children <2 years: safety not established.
Known hypersensitivity to Centella or Apiaceae family.

Drug interactions (pharmacodynamic caution):

CNS depressants (benzodiazepines, barbiturates, alcohol): Additive sedation possible.
Antidiabetic drugs / insulin: May potentiate hypoglycemia.
Statins / lipid-lowering agents: In vitro inhibition of CYP3A4 is negligible; clinically significant interaction unlikely, but monitor lipid levels (additive cholesterol-lowering effect reported).
Anticoagulants/antiplatelets: No strong evidence of interaction, but caution due to possible collagen stabilization affecting platelet function.

Perioperative: Discontinue 2 weeks before scheduled surgery (theoretical impact on glucose regulation and sedation).

Molecular

Molecular Size

Compound	Molecular Formula	Molecular Weight (g/mol)
Asiaticoside	C₄₈H₇₈O₁₉	959.12
Madecassoside	C₄₈H₇₈O₂₀	975.11
Asiatic acid	C₃₀H₄₈O₅	488.70
Madecassic acid	C₃₀H₄₈O₆	504.70

The glycosides (asiaticoside, madecassoside) are large, polar molecules with poor passive diffusion. Their respective aglycones (asiatic acid, madecassic acid) are much smaller and more lipophilic, enabling better cellular and blood–brain barrier penetration.

Activates

Activates (Biological Targets)

“Activates” in this context refers to the enzymes, receptors, transcription factors, and signaling molecules positively regulated by Centella triterpenes.

Signalling pathways & transcription factors:

TGF-β1/Smad2/3 – primary fibrogenic and healing signal
Nrf2/ARE – master antioxidant response
AMPK – metabolic sensor (enhances autophagy, anti-inflammation)
eNOS (via PI3K/Akt) – endothelial nitric oxide production → vasodilation
PPAR-γ – anti-inflammatory, adipogenic modulation
BDNF/TrkB/CREB – synaptic plasticity & neuroprotection
VEGF & FGF-2 – angiogenesis
Choline acetyltransferase – acetylcholine synthesis

Cellular events activated:

Fibroblast proliferation and migration
Collagen I, III, and fibronectin gene expression
Keratinocyte proliferation (re-epithelialization)
M2 macrophage polarization (anti-inflammatory, pro-resolving)
Mucin secretion (gastric mucosa)

Absorption

Absorption & Pharmacokinetics

Oral route:

Asiaticoside and madecassoside are prodrugs; they are poorly absorbed intact.
Colonic microbiota (Bacteroides, Bifidobacterium) hydrolyze the glycosidic bonds via β-glucosidases, releasing asiatic acid and madecassic acid.
The aglycones are absorbed by passive transcellular diffusion across enterocytes.
Bioavailability: ~20–30% for total triterpenes; enhanced by lipid-based formulations (e.g., with medium-chain triglycerides) and by piperine.
Tₘₐₓ (time to peak plasma concentration): 1–2 hours.
Plasma half-life: asiatic acid ~2–4 hours; madecassic acid slightly longer. Accumulation may occur in tissues with repeated dosing.
Distribution: extensive; crosses blood–brain barrier and enters skin, joint synovium, gastric mucosa.

Topical route:

Penetrates intact stratum corneum; absorption enhanced by liposomes, ethosomes, or microemulsion gels.
Local concentration in dermis is sufficient to activate fibroblasts without significant systemic absorption.

Metabolism:

Aglycones undergo phase II conjugation (glucuronidation, sulfation) in liver and enterocytes. Conjugates are excreted in bile and urine.

Biological

Biological Cycle Pathways

These are the core molecular circuits and metabolic cycles modulated by Centella that underpin its therapeutic effects.

Collagen homeostatic cycle

Proline/lysine hydroxylation → procollagen triple helix formation → secretion → cleavage to tropocollagen → lysyl oxidase cross-linking → mature collagen fiber.
Centella upregulates prolyl hydroxylase and lysyl oxidase, while suppressing MMP-1,2,9 via TIMP-1 induction, pushing the cycle toward net deposition.

Inflammation resolution cycle

NF-κB inhibition → reduced COX‑2, iNOS, TNF‑α, IL‑1β, IL‑6 → shift from Th1 to Th2/M2 → increased IL‑10, TGF‑β → phagocytosis of apoptotic neutrophils → resolution.

Antioxidant cycle (Nrf2-ARE)

Triterpenes disrupt Keap1-Nrf2 binding → Nrf2 nuclear translocation → ARE activation → upregulation of glutathione (GSH) synthesis, catalase, superoxide dismutase, heme oxygenase-1 → cellular redox balance restored.

Angiogenesis cycle

VEGF/VEGFR2 binding → PI3K/Akt and MAPK/ERK cascades → endothelial proliferation, migration, tube formation → new capillary networks perfuse healing tissue.

Neuroplasticity cycle

BDNF → TrkB → Ras/ERK and PI3K/Akt → CREB phosphorylation → synaptic protein expression (synaptophysin, PSD‑95) → dendritic arborization and long-term potentiation.

Bone & cartilage remodelling (minor)

Increase in alkaline phosphatase, osteocalcin in osteoblasts; inhibition of osteoclast differentiation via RANKL/OPG ratio modulation.

Complete

Complete Researched Sequence: Mechanism of Action

This stepwise, multi-tissue pathway integrates pharmacological data into a comprehensive mechanism.

Step 1 – Ingestion & biotransformation

Oral supplement → glycosides (asiaticoside, madecassoside) reach distal small intestine/colon → bacterial β-glucosidase hydrolysis → release of asiatic acid and madecassic acid → absorption into portal circulation.

Step 2 – Systemic distribution

Aglycones circulate partly bound to albumin → reach target tissues (skin dermis, vascular endothelium, brain, gastric mucosa, peripheral nerves). Unconjugated fraction crosses lipid bilayers, including the blood–brain barrier.

Step 3 – Tissue-specific receptor-independent modulation

Unlike classical ligands, asiatic acid enters cells partly via passive diffusion and partly via caveolin-mediated endocytosis. Inside the cell, it interacts with intracellular signaling complexes:

A) In dermal fibroblasts – Wound healing & scar modulation

Increases TGF-β1 synthesis and its receptor expression.
Sustains Smad2/3 phosphorylation → Smad2/3–Smad4 complex nuclear translocation → binds Smad-binding element (SBE) on COL1A1, COL3A1, FN1 promoters → massive upregulation of type I & III collagen, fibronectin.
Simultaneously inhibits Smad7 (negative feedback inhibitor) → prolongs signal.
Suppresses MMP-1 and MMP-2 transcription while upregulating TIMP-1 → prevents collagen degradation → increased tensile strength, reduced scar hypertrophy.
Activates PI3K/Akt → enhances fibroblast migration into wound bed.

B) In endothelial cells – Vascular integrity & microcirculation

Akt-mediated phosphorylation of eNOS → NO release → vasodilation of precapillary sphincters → improved microvascular flow.
Nrf2 activation → reduction of ROS-induced endothelial apoptosis → preservation of capillary density.
Stimulation of VEGF secretion from fibroblasts → supports angiogenesis in ischemic tissue.

C) In inflamed tissue – Anti-inflammatory cascade

IκBα stabilization → NF-κB retained in cytoplasm → transcription of COX‑2, iNOS, TNF‑α, IL‑1β suppressed.
p38 MAPK and JNK phosphorylation inhibited → reduced pro-apoptotic signals in epithelial cells.
Madecassoside selectively activates STAT6 → M2 macrophage polarization → IL‑10 and TGF‑β production → resolution of chronic inflammation.

D) In central nervous system – Neuroprotection & anxiolysis

Asiatic acid crosses BBB → activates BDNF transcription via CREB phosphorylation → TrkB receptor activation → downstream MAPK/ERK and PI3K/Akt → dendritic sprouting, synapse formation.
Increases choline acetyltransferase activity → elevated acetylcholine levels in cortex and hippocampus → cognitive enhancement.
Modulates GABAergic system: upregulates glutamic acid decarboxylase (GAD67) → increased GABA synthesis; enhances GABAA receptor binding → anxiolysis without sedation at therapeutic doses.
Reduces amyloid-β burden: downregulates BACE1 (β-secretase), upregulates ADAM10 (α-secretase) → promotes non-amyloidogenic APP processing.

E) In gastric mucosa – Ulcer healing

Stimulates COX‑1-mediated prostaglandin E₂ synthesis → increased mucus-bicarbonate barrier, mucosal blood flow.
Promotes epithelial cell mitosis via EGF receptor transactivation → accelerated restitution.

F) In peripheral nerve – Diabetic neuropathy

Schwann cell proliferation and migration enhanced via ERK1/2.
NGF (nerve growth factor) and NT‑3 expression upregulated in injured nerve microenvironment.
Microvascular improvement (eNOS activation) restores endoneurial blood flow, reducing ischemic nerve damage.

Step 4 – Systemic homeostatic reset

Long-term modulation of TGF-β and collagen cycles, sustained Nrf2 activity, and chronic anti-inflammatory tone produce cumulative improvements in venous tone, skin texture, cognitive reserve, and ulcer healing rates.

Synergy

Synergy Combinations

Combination	Synergy Mechanism	Application
Gotu Kola + Vitamin C	Ascorbic acid is a cofactor for prolyl/lysyl hydroxylase in collagen synthesis; Centella upregulates collagen gene expression. Together they greatly increase functional mature collagen deposition.	Skin ageing, wound healing, post-surgery
Gotu Kola + Horse Chestnut (escin)	Escin seals leaky capillaries and improves venous return; Centella strengthens venous wall collagen. Complementary on oedema and venous insufficiency.	Chronic venous insufficiency, lymphedema
Gotu Kola + Bacopa monnieri	Both enhance dendritic arborisation (Bacopa via synaptophysin, Centella via BDNF) and cholinergic activity. Additive effect on memory retention and anxiety.	Cognitive decline, ADHD, exam stress
Gotu Kola + Curcumin	Curcumin inhibits NF-κB at early step, Centella provides pro-resolution signals (M2 polarization) and collagen synthesis. Potent anti-inflammatory → pro-healing transition.	Osteoarthritis, scleroderma, chronic wounds
Gotu Kola + Hyaluronic acid (topical)	HA provides hydrating scaffold, Centella stimulates fibroblast infiltration and collagen deposition.	Atrophic scars, burns, deep wrinkles
Gotu Kola + Zinc	Zinc is critical for MMP activity, protein synthesis, and immune function; Centella drives the transcription of matrix proteins.	Chronic leg ulcers, acne scar repair
Gotu Kola + Ginkgo biloba	Ginkgo improves cerebral and peripheral blood flow; Centella repairs endothelium and promotes neuroplasticity.	Age-related cognitive decline, diabetic microangiopathy

Chronic

Chronic Conditions Where Therapeutic Use Is Underestimated

These are high-burden conditions where Centella extract shows clinically meaningful benefit in published evidence, yet remains underutilized in mainstream practice.

Diabetic Polyneuropathy

Why underestimated: Standard care focuses on glycaemic control, gabapentinoids, and duloxetine. Centella directly targets the pathogenic triad: microvascular rarefaction, oxidative stress, and deficient neurotrophic support.
Evidence: Human studies show improved nerve conduction velocity, reduction in pain scores, and enhanced sensory function when TTF is added to standard therapy. The dual angiogenic-neuritogenic action makes it a disease-modifying adjunct, not merely symptomatic.

Systemic Sclerosis (Scleroderma)

Why underestimated: Treatment relies heavily on immunosuppressives. Centella, especially its madecassoside-rich fraction, acts as a physiological TGF-β modulator, softening skin, reducing digital ulcers, and improving mouth opening through balanced collagen remodeling without dangerous immunosuppression.
Evidence: Several RCTs have reported significant improvement in skin score and Raynaud’s phenomenon severity.

Postmastectomy Lymphedema

Why underestimated: Complex decongestive therapy is the standard; pharmacological adjuncts are few. Centella extract reduces limb volume, decreases heaviness, and improves tissue elasticity by reinforcing lymphatic capillary walls and reducing interstitial fibrosis.
Evidence: Clinical trials show a 5–10% arm volume reduction over 12 weeks with oral TTF, exceeding placebo.

Chronic Periodontitis (topical adjunct)

Why underestimated: Dentists rely on scaling/root planing and antibiotics. A topical gel containing Centella triterpenes significantly improves probing pocket depth and clinical attachment level by suppressing gingival inflammation and promoting periodontal ligament fibroblast regeneration.
Evidence: Split-mouth RCTs confirm superior outcomes over placebo gel after scaling.

Fibrotic Liver Disease (NASH / early cirrhosis)

Why underestimated: Antifibrotics for liver are scarce. Asiatic acid downregulates hepatic stellate cell activation and collagen synthesis while enhancing collagenase activity. In animal models and small human pilot studies, it reduced fibrosis markers and liver stiffness.
Potential: A safe, oral antifibrotic that could bridge the gap between lifestyle modification and transplant in fatty liver disease.

Gastric Ulcer (non-H. pylori, NSAID-induced)

Why underestimated: Proton pump inhibitors dominate. Centella not only reduces acid-driven mucosal damage but actively stimulates epithelial restitution, angiogenesis in the ulcer bed, and strengthens the mucus barrier—addressing the mucosal defence deficit that PPIs alone cannot fix.
Value: Particularly useful in refractory ulcers or patients requiring long-term low-dose aspirin where complete healing remains elusive.
These conditions share a common thread of chronic tissue remodeling, microangiopathy, and low-grade inflammation—precisely the pathophysiological cascade where Centella’s pleiotropic mechanisms offer a unique, non-toxic therapeutic advantage that modern guidelines still overlook.