Lolot pepper

Lolot pepper is a perennial herb with a creeping rhizome that roots at the nodes; young branches grow erect to about 30–40 cm before sprawling to the ground, and the green stems are striped. The simple alternate leaves are heart-shaped and thin, 8–10 cm long and 8–11 cm wide, glossy above with scattered oil glands, paler beneath, with five main veins arising from the base; the petiole is sheathing. Small white flowers crowd into erect axillary spikes 1–2 cm long; the fruit is a small one-seeded berry. The whole plant is strongly aromatic and slightly pungent — the signature flavour of grilled beef wrapped in lolot leaves. The former name Piper lolot C.DC. is now treated as a synonym of Piper sarmentosum Roxb.

According to Kew's Plants of the World Online the native range of Piper sarmentosum is southern China to Indo-China and northern Australia, in the wet tropical biome. It occurs wild in south-central and south-east China, Hainan and Tibet; across Indo-China (Vietnam, Laos, Cambodia, Thailand, Myanmar); in the Andaman Islands, Peninsular Malaysia, Sumatra, Borneo, Java, Maluku and the Philippines; in Papua New Guinea; and in the Northern Territory and Queensland of Australia. It has been introduced to Hawaii, Sri Lanka, India, Madagascar, Mauritius, Réunion, the Caroline Islands and Trinidad-Tobago. MyBIS (2023) reports it as widespread across Southeast Asia, typically in wet forest or near villages under shade, and in Malaysia it is considered a weed because it spreads so easily. In Vietnam it grows wild along ditches and field margins and under moist shade, is grown around houses as a culinary herb, and occurs from sea level to about 1000 m.

Steam distillation of dried leaves yields about 1.10% oil (v/dry weight) with 31 components, dominated by spathulenol 21.0%, myristicin 18.8%, β-caryophyllene 18.2% and (E,E)-farnesol 10.5% (Malaysian Journal of Analytical Sciences). Composition varies sharply with origin: oil from Vietnamese-grown plants is aromatic in character, with benzyl benzoate 49.1%, benzyl alcohol 17.9%, the phenylmethyl ester of 2-hydroxybenzoic acid 10.0% and 2-butenylbenzene 7.9% (Journal of the Oil Chemists' Society 63(3)), whereas Chinese material reaches 65.22% myristicin. Beyond the oil, the species is rich in piperamide-type amides — pellitorine, sarmentine, sarmentosine, guineensine, brachyamide B, nigrinodine — concentrated in fruits and roots; plus flavonoids (naringenin, quercetin, didymin, hesperidin, rutin) largely in the leaves, phenylpropanoids (trans-asarone, γ-asarone, 2,4,5-trimethoxypropenylbenzene), lignans and neolignans (sesamin, asarinin, andamanicin) and sterols (β-sitosterol, stigmasterol). An LC-MS metabolite study (Natural Products and Bioprospecting, 2024) annotated 154 metabolites: leaves are rich in flavonoids, lignans and phenylpropanoids, stems in aporphine alkaloids (magnoflorine, piperolactam A and B), and fruits and roots in piperamides.

Culinary use centres on the leaf as a wrapper: Vietnamese grilled beef in lolot leaves, minced-pork lolot rolls and snail stew with banana; Lao, Thai (chaphlu), Indonesian and Malaysian (kaduk) cuisines use the leaf too, and Zhanjiang in Guangdong has a lolot-leaf rice dish. Southeast Asian folk medicine employs leaves and roots — pounded for headache and bone pain, decocted for cough, influenza, toothache and rheumatism, with the root chewed for toothache or decocted as a wash. The pharmacological review in Pharmaceutical Biology (2011) collates evidence for anti-inflammatory, analgesic, antipyretic, antibacterial, antioxidant, acetylcholinesterase-inhibiting, anticancer and antimalarial activities; animal studies report reduced atherosclerotic lesions, blood-glucose lowering and anti-osteoporotic effects. A 2023 study in the International Journal of Molecular Sciences isolated 34 compounds from the leaves, finding kadukoside inhibited Septoria tritici (IC50 5.0 µM) and 94% of Phytophthora infestans growth at 125 µM, while isoasarone and trans-asarone showed anthelmintic activity (IC50 0.9–2.04 mM).

On safety, lolot pepper is considered safe at normal culinary doses and is included in the Malaysian Herbal Monograph 2015; no human clinical trials have yet defined a medicinal dose, so concentrated extracts should not be taken long-term on one's own initiative. Caution applies in pregnancy and breastfeeding (some phenylpropanoids such as asarone are pharmacologically potent), in people taking anticoagulants or antihypertensives, and essential oil should never be applied undiluted to skin. For conservation, the species is Not Evaluated by the IUCN and is not in CITES; its natural range is very wide, it seeds and roots readily from cuttings, and it is widely grown as a culinary herb, so it is not threatened. In parts of its introduced range (Hawaii, Sri Lanka, Madagascar…) and in Malaysia it can become weedy. Priorities are to conserve Vietnamese native genotypes, avoid hybridisation with related Piper species, and protect the moist streamside and ditch-side habitats where it grows wild.