Lagundi

Lagundi leaves contain flavonoids (vitexin, isovitexin), terpenoids (squalene, phytol), phenolics (pyrogallol, salicylic acid), and the sterol sitosterol, which exert antitussive and anti-asthmatic effects by modulating airway inflammation and bronchospasm. In vitro, dichloromethane leaf extracts achieved a 5-log reduction in SARS-CoV-2 plaque formation in Vero E6 cells at non-cytotoxic concentrations, and methanolic leaf extracts produced 16 mm zones of inhibition against Escherichia coli at 3,000 µg/mL.

Origin & History

Vitex negundo L. is native to Southeast and South Asia, distributed widely across the Philippines, India, China, Sri Lanka, and Indonesia, typically thriving in tropical and subtropical climates along riverbanks, forest margins, and disturbed land up to 1,500 meters elevation. It is a large aromatic shrub or small tree in the family Lamiaceae, favoring well-drained soils with high humidity and seasonal rainfall. In the Philippines, it is cultivated and wildcrafted for both traditional medicine and government-approved herbal preparations, with the Department of Health officially endorsing it as one of ten approved medicinal plants.

Historical & Cultural Context

Lagundi has been integral to traditional medicine in the Philippines, India, China, and across South and Southeast Asia for centuries, appearing in Ayurvedic texts as 'Nirgundi' where it was prescribed for pain, fever, worm infestations, and respiratory diseases. In Filipino ethnomedicine, leaves, stems, roots, and flowers were all employed: leaves were boiled for coughs, asthma, and skin diseases; roots were used as a tonic and febrifuge; and flowers were prepared for diarrhea and cholera. The Philippine Department of Health formally recognized Lagundi in the 1990s under its Traditional and Alternative Medicine Act (Republic Act 8423), elevating it to one of ten government-approved herbal medicines with official monographs. In Chinese traditional medicine, Vitex negundo (known as 'Huang Jing') has been documented in the Bencao Gangmu (Compendium of Materia Medica, 1596) for resolving wind-heat conditions, relieving headaches, and treating eye disorders.

Health Benefits

- **Antitussive and Anti-Asthmatic Activity**: Flavonoids vitexin and isovitexin in Lagundi leaves are proposed to relax bronchial smooth muscle and suppress airway hypersensitivity, supporting its government-approved use as a cough and asthma remedy in the Philippines.
- **Antioxidant Protection**: Pyrogallol, squalene, and phytol identified by GC-MS in leaf and stem extracts show dose-dependent DPPH free radical scavenging activity, with trifoliate leaf extracts demonstrating the strongest inhibition among tested fractions.
- **Antimicrobial Activity**: Methanolic leaf extracts inhibit both Gram-positive organisms (Staphylococcus aureus, Bacillus subtilis) and Gram-negative organisms (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi) with zones of inhibition up to 16 mm at 3,000 µg/mL, attributed to flavonoids, tannins, and saponins disrupting bacterial cell membranes.
- **Antifungal Potential**: Crude leaf and stem extracts show activity against Aspergillus niger, with phytochemical constituents including saponins and phenolics contributing to membrane disruption in fungal cells.
- **Antiviral Activity**: DCM leaf extract reduced SARS-CoV-2 plaque formation by 5 logs in Vero E6 cell assays at the maximum non-cytotoxic dose, suggesting broad antiviral potential mediated by lipophilic terpenoid and phenolic constituents.
- **Anti-Inflammatory Properties**: Salicylic acid and 22,23-dihydro-α-spinasterol-β-d-glucoside isolated from methanolic leaf extracts contribute anti-inflammatory signaling, with sitosterol providing additional cyclooxygenase-modulating sterol activity.
- **Insecticidal and Pest-Repellent Effects**: Isolated salicylic acid from Lagundi leaf extracts demonstrates residual film toxicity against the stored-grain pest Tribolium castaneum, supporting ethnobotanical use of leaves as grain protectants.

How It Works

The antioxidant activity of Lagundi is driven primarily by polyphenols pyrogallol and phenolic terpenoids phytol and squalene, which donate hydrogen atoms to neutralize reactive oxygen species in a dose-dependent manner, as confirmed by DPPH inhibition assays across leaf and stem fractions. Antimicrobial action is mediated by flavonoids, tannins, saponins, and glycosides that disrupt bacterial and fungal cell wall integrity and membrane permeability, leading to leakage of intracellular contents, with tannins additionally precipitating microbial surface proteins. Antiviral effects against SARS-CoV-2 are attributed to lipophilic DCM-extractable compounds—likely terpenoids and sterols—that interfere with viral entry or replication machinery in host cells, though the precise molecular target (e.g., protease inhibition, spike protein binding) has not been elucidated in published data. Anti-inflammatory and antitussive pathways are hypothesized to involve salicylic acid inhibiting prostaglandin biosynthesis and vitexin/isovitexin modulating histamine release and bronchial smooth muscle tone, though human receptor-binding studies are not yet available.

Scientific Research

The current body of evidence for Lagundi consists predominantly of in vitro studies and phytochemical characterization research, with no indexed randomized controlled trials reporting sample sizes or effect sizes in the available literature. GC-MS profiling studies have quantified specific volatile compounds (acrolein at 15.24% in trifoliate leaf extract, hydroquinone at 4.76% in stem extract) and correlated these with antioxidant activity, but these are observational chemical analyses rather than interventional trials. Antimicrobial disk diffusion assays at 3,000 µg/mL and antiviral plaque reduction assays in Vero E6 cells represent the strongest mechanistic data available, yet neither translates directly to human clinical efficacy or therapeutic dosing. Notably, the Philippine Department of Health has approved Lagundi syrup as a standard treatment for cough and mild asthma based on accumulated traditional evidence and limited local clinical observation, but peer-reviewed RCT data with quantified outcomes are not publicly indexed in the sources reviewed.

Clinical Summary

No peer-reviewed human clinical trials with defined sample sizes, randomization, or quantified effect sizes were identified for Lagundi in the current literature search. The strongest available evidence is a 5-log SARS-CoV-2 reduction in a cell-based plaque assay (Vero E6 model) using DCM leaf extract at non-cytotoxic concentrations, and zone-of-inhibition data up to 16 mm against E. coli in disk diffusion assays. The Philippine government's endorsement as an approved herbal medicine for cough and asthma represents regulatory-level acknowledgment of traditional efficacy, but this is not equivalent to evidence from controlled clinical trials. Confidence in human clinical outcomes remains low-to-moderate; prospective trials with standardized extracts, defined dosing, and validated respiratory endpoints are needed to substantiate the in vitro findings.

Nutritional Profile

Lagundi leaves are not consumed as a dietary staple and lack standard macronutrient profiles; their significance lies in phytochemical content rather than caloric or micronutrient contribution. GC-MS analysis identifies major volatile compounds including acrolein (15.24% in trifoliate leaf extract), hexadecenoic acid (a saturated fatty acid), squalene (a triterpene precursor), phytol (a diterpene alcohol), and naphthalene in leaf and stem fractions. Phenolic compounds include pyrogallol, salicylic acid, hydroquinone (4.76% in stem extract), and tannins; flavonoids vitexin and isovitexin are present alongside sterols 22,23-dihydro-α-spinasterol-β-d-glucoside and sitosterol. Saponins, coumarins, reducing sugars, glycosides, and alkaloids are confirmed by qualitative phytochemical screening; exact quantitative concentrations for most secondary metabolites vary by leaf type (trifoliate vs. pentafoliate), plant part (leaf vs. stem), solvent polarity, and extraction method, limiting direct cross-study comparisons.

Preparation & Dosage

- **Standardized Syrup (Philippine DOH-approved)**: 300 mg per 5 mL syrup; standard adult dose is 15 mL (three times daily) for cough and mild asthma as per official Philippine herbal pharmacopeia guidance.
- **Decoction (Traditional Leaf Tea)**: 6 grams of fresh leaves boiled in 2 cups of water for 15 minutes, strained and consumed as 1 cup two to three times daily for respiratory complaints.
- **Methanolic Leaf Extract (Research Form)**: Tested in vitro at 3,000 µg/mL for antimicrobial activity and at varying concentrations for DPPH antioxidant assays; no standardized human supplemental dose derived from these concentrations.
- **DCM Leaf Extract (Antiviral Research Form)**: Used at maximum non-cytotoxic dose in Vero E6 cell assays (approximately 50 µg/mL equivalent); not formulated for human consumption in this form.
- **Dried Leaf Capsule/Tablet**: Commercially available in the Philippines at 300–500 mg per capsule; frequency follows traditional guidelines of two to three times daily, though bioavailability data for capsule forms are unavailable.
- **Standardization Note**: No internationally recognized standardization percentage for vitexin or isovitexin content has been established; Philippine preparations are standardized by weight of dried leaf material rather than marker compound concentration.

Synergy & Pairings

Lagundi is traditionally combined with ginger (Zingiber officinale) in Filipino herbal preparations for respiratory conditions, where ginger's 6-gingerol and shogaol contribute complementary anti-inflammatory and bronchodilatory effects alongside Lagundi's vitexin-mediated airway modulation. In Ayurvedic formulations, Nirgundi is often paired with Tulsi (Ocimum sanctum) for synergistic antimicrobial and expectorant effects, with Tulsi's eugenol and ursolic acid reinforcing membrane-disrupting activity against respiratory pathogens. The antioxidant phenolics pyrogallol and phytol in Lagundi may exhibit additive free radical scavenging when combined with vitamin C or quercetin-rich botanicals, though these combinations have not been formally studied in controlled trials.

Safety & Interactions

Human safety data for Lagundi are limited due to the predominance of in vitro and traditional-use studies; no serious adverse events have been formally documented in indexed clinical literature, but the absence of safety trials does not confirm safety across all populations. The antiviral DCM extract was tested at maximum non-cytotoxic concentrations in Vero E6 cells with no observed cellular toxicity, and Philippine DOH-approved syrup preparations have a long record of use without widely reported serious adverse reactions, though systematic pharmacovigilance data are lacking. Potential drug interactions have not been studied; given the presence of salicylic acid, theoretical interactions with anticoagulants (warfarin), NSAIDs, and antiplatelet agents warrant caution, and the flavonoid content may theoretically modulate cytochrome P450 enzyme activity. Lagundi is contraindicated during pregnancy based on traditional precautionary guidance and the lack of reproductive safety data; lactating women and young children should use only under medical supervision, and individuals with aspirin sensitivity should exercise caution given salicylic acid content.