Piper retrofractum (Javanese Long Pepper / Balinese Long Pepper)
1. Identity and Botanical Description
Piper retrofractum Vahl, commonly known as the Balinese long pepper or Javanese long pepper, is a flowering vine in the family Piperaceae, cultivated for its fruit, which is usually dried and used as a spice and seasoning. This species is regarded as native to Java, Indonesia. It is a dioecious, evergreen climbing shrub widespread in Southeast Asia, including the Philippines, Indonesia, Malaysia, Thailand, Vietnam, Cambodia, Laos, and southern China.
This liana grows up to 10 meters long, supported by adhesive roots, with glabrous, coriaceous leaves that are ovate to oblong, measuring 8–20 cm long and 3–13 cm wide, often featuring sunken gland dots. Its erect or patent spikes produce cylindrical infructescences 2–4 cm long, bearing connate berries that are green and pungent when unripe, turning red-brown upon maturity. The plant thrives in wet tropical biomes, particularly in deciduous forests on poor soils up to 600 m altitude, thickets at low elevations, and even along beaches, with semi-wild populations in certain regions.
Synonyms and Common Names
The plant is also known by the botanical synonym Piper chaba Hunter. Another synonym in the botanical literature is Piper officinarum (Miq.) C.DC., and it is found mainly in tropical and subtropical regions. Common names across various regions include Javanese Long Pepper, Balinese pepper, Bengal pepper, Jaborandi pepper, Java long pepper, and Tabia bun. In Cambodia it is known as dei-phlei, and in Thailand as deebplee. In the Malay Archipelago, the fruit was once known as cabai; its culinary popularity was eventually superseded by the chili, brought from the New World by European traders, resulting in a semantic shift in which the new crop became cabai and the old became cabai jawa.
In Indian Ayurvedic tradition, the plant is referred to as Chavya and is described as one of the key ingredients in classical Ayurvedic formulations, including Chandraprabha vati, where the root is the part used.
Cultivation and Production
Long pepper has mass cultivation in the central part of Thailand, especially in the Kanchanaburi, Ratchaburi, Phetchaburi, and Chanthaburi provinces. Along with black pepper (Piper nigrum L.), P. retrofractum is a member of Piper with high economic value. Both species are aromatic herbs; however, P. retrofractum has a harsher aroma than pepper and is chiefly recognized as a medicinal plant, while pepper is primarily a food spice.
Plant Parts and Common Forms
- The plant is gathered from the wild for mainly local use as a condiment and medicinal herb. Leaves and berries are edible; both ripe and unripe fruits are used as a spice.
- Dried fruits of P. retrofractum are commonly used as spices and in traditional medicines as an expectorant, antitussive, antipyretic, and treatment for gastrointestinal ailments.
- The plant is more pungent than Piper nigrum, but also sweeter. The root is chewed (with the saliva swallowed), or a decoction of the root is drunk as a treatment for colic, dyspepsia, and gastralgia.
- The roots are also used to treat toothaches, wounds, and seizures, and the leaves are used for mouthwash.
2. Traditional and Historical Use
Indonesia
In traditional Indonesian contexts, P. retrofractum served dual roles as both a culinary spice and a medicinal herb, often incorporated into herbal preparations for digestive and respiratory ailments, reflecting its longstanding significance in pre-colonial societies. In Indonesian traditional medicine, it was used to improve stamina and for its aphrodisiac effect and beneficial effect on erectile dysfunction. Ethnic groups used the plant as a traditional medicine to cure digestive disorders, improve blood circulation, and treat asthma, influenza, rheumatism, and hypertension.
Thailand
In Thai ethnobotanical traditions, Piper retrofractum, referred to as dipli or dipli-chueak, holds cultural importance as a "hot"-flavored plant used to enhance vitality through improved digestion and blood circulation, and as a component of trikatu formulations that balance bodily elements and promote overall well-being. Locals in Thailand use P. retrofractum fruit as a key ingredient in various recipes of their traditional medicine and foods.
China
In China, the plant was used for vomiting, hiccups, stomachaches, and diarrhea due to coldness in the stomach.
Ayurveda (India)
In Ayurveda, Chavya (Piper retrofractum) is recognized as one among the Panchakola groups of spices, with the root and fruit considered useful in treating indigestion, abdominal colic, poisoning, and anorexia. The plant holds significant importance in Ayurveda due to its diverse medicinal properties, including the ability to balance Vata and Kapha doshas, with digestive, respiratory, and anti-inflammatory actions. It is widely used in formulations like Trikatu and Chavyadi Churna to enhance metabolic function and support overall health.
Philippines and Southeast Asian Ethnomedicine
In Filipino traditional medicine, a handful of leaves are salted and oiled, then heated over the embers of a fire and stroked over the entire body for treating postpartum fevers and chills. The roots and fruits of P. retrofractum were used as stimulants and to treat asthma, bronchitis, hemorrhoids, fever, liver diseases, jaundice, edema, and abdominal pain.
Historically, hihatsumodoki (the Japanese name for P. retrofractum) fruits were used in traditional medicine as digestive aids, stimulants, carminatives, and agents for intestinal disorder treatment and postpartum pretreatment in women.
3. Key Constituents and Active Compounds
The main chemical constituents that have been isolated and identified from P. retrofractum are amides, alkaloids, phenylpropanoids, alkyl glycosides, and lignans. The plant's medicinal uses are linked to its phytochemical composition, which includes alkaloids, saponins, tannins, flavonoids, steroids, terpenoids, and glycosides.
Alkaloids and Amides
P. retrofractum extract contains five prominent constituents — piperanine, piperine, isopiperine, chavicine, and isochavicine — of which piperine is considered an important bioactive component. Piperidine alkaloids from P. retrofractum Vahl (PRPAs), including piperine, pipernonaline, and dehydropipernonaline, have been isolated as anti-obesity constituents through a peroxisome proliferator-activated receptor δ (PPARδ) transactivation assay.
Phytochemical studies of the main secondary metabolites of P. retrofractum include several types of alkaloids such as piperine, pipernonaline, guineensine, and piperoctadecalidine, as well as fruit essential oils. Piper retrofractum Vahl also yields retrofractamide-D, a distinctive unsaturated amide that has been fully characterized.
A review of the literature revealed that 97 compounds (besides volatile constituents) have been reported, including seventy-seven amides, four amide glycosides, eleven alkyl glycosides, one phenylpropanoid, two phenylpropanoid glycosides, and two lignans. Among them, twenty-seven new phytochemicals have been isolated from various parts of P. retrofractum.
From the hexane and methanol extracts of P. retrofractum, one bis-epoxy lignan (−)-sesamin and two amides, pellitorine and piplartine, have been isolated.
Phenylpropanoids and Glycosides
Two new compounds, piperoside and isoheptanol 2(S)-O-β-D-xylopyranosyl (1→6)-O-β-D-glucopyranoside, along with ten known phenylpropanoids and alkyl glycosides, have been isolated from the leaves of Piper retrofractum.
From the fruits of P. retrofractum, two new amides, four new amide glucosides (retrofractosides A–D), and two new phenylpropanoid glucosides (retrofractosides E and F), along with 24 known compounds, have been isolated.
Piperine Content
For Piper retrofractum Vahl, piperine contents of 3.1–4.5% have been indicated in the literature. Total organic acids, total free amino acids, and piperine decrease with increasing fruit maturation, reaching minima at the red maturity stage.
4. Mechanisms of Action
AMPK and PPARδ Activation
The molecular mechanism of the piperidine alkaloids was investigated in 3T3-L1 adipocytes and L6 myocytes, where PRPA treatment activated AMP-activated protein kinase (AMPK) signaling and PPARδ protein, and also regulated the expression of lipid metabolism-related proteins.
NF-κB Inhibition
In laboratory assays, P. retrofractum extract was found to significantly reduce LPS, nitric oxide, COX-2, IL-6, IL-1, and NF-κB through the TLR4 axis. These findings suggest that Piper retrofractum extract possesses anti-inflammatory properties by reducing proinflammatory cytokine production through inhibition of NF-κB signaling pathway.
PPARδ/AMPK and Antiphotoaging Pathways
P. retrofractum extract (PRE) treatment activated PPARδ and AMPK, consequently upregulating mitochondrial synthesis and reducing ROS production. Additionally, PRE inhibited MMP expression via suppressing MAPK and AP-1. PRE downregulated UVB-induced inflammatory reactions by inhibiting NF-κB activity and also enhanced TGF-β and the Smad signaling pathway, thereby promoting procollagen gene transcription.
AKT and ERK Pathways in Lymphangiogenesis
Treatment with P. retrofractum extract (PRE) and piperine significantly promoted proliferation, migration, and tube formation in human dermal lymphatic microvascular endothelial cells (HDLECs); furthermore, PRE and piperine significantly promoted the phosphorylation of AKT and ERK proteins in HDLECs, and pretreatment with AKT and ERK inhibitors significantly attenuated PRE- and piperine-induced lymphangiogenesis.
Neurotrophic Activity
One compound isolated from P. retrofractum fruits was found to enhance the neurite outgrowth of NGF-mediated PC12 cells at concentrations ranging from 0.1 to 10 μM. Among isolated compounds, two alkaloids (dehydropipernonaline and pipernonaline) displayed significant neurite outgrowth (NOG) effects in the presence of nerve growth factor in a dose-dependent manner; pipernonaline showed 24.3% NOG positive at 100 µM and dehydropipernonaline showed 21.1% NOG positive at 100 µM, with the piperidine skeleton identified as key to NOG activity.
5. Scientific Evidence by Area of Use
5.1 Anti-Obesity and Metabolic Effects
The fruits of Piper retrofractum Vahl had been used for their gastroprotective and cholesterol-lowering properties in traditional medicine, but their anti-obesity activity was previously unexplored.
Preclinical evidence (animal/in vitro): Piperidine alkaloids from P. retrofractum Vahl (PRPAs), including piperine, pipernonaline, and dehydropipernonaline, were isolated as anti-obesity constituents through a PPARδ transactivation assay. The molecular mechanism was investigated in 3T3-L1 adipocytes and L6 myocytes; PRPA treatment activated AMPK signaling and PPARδ protein and regulated the expression of lipid metabolism-related proteins. PRPA administration significantly reduced body weight gain without altering food intake, and reduced high-fat diet-induced triglyceride accumulation in the liver.
Evidence strength: Preclinical only (cell culture and high-fat diet mouse model). No human clinical trials on anti-obesity effects have been identified in the literature.
5.2 Anti-inflammatory Effects
Preclinical evidence (in vitro / animal model): Research aimed at identifying Indonesian medicinal plants capable of inhibiting NF-κB found that Piper retrofractum extract demonstrated promising inhibitory effects on NF-κB and proinflammatory molecules. Notably, P. retrofractum extract was found to enhance the survival of human keratinocytes by protecting them from cell death induced by TRAIL; moreover, immunohistochemistry analysis in an imiquimod-induced skin inflammation mouse model showed downregulation of COX-2 and IL-1β expression upon treatment with the extract.
Evidence strength: Preclinical (in vitro and mouse model). No randomized clinical trials assessing P. retrofractum extract for inflammation in humans have been identified.
5.3 Antiphotoaging and Skin Effects
Preclinical evidence (in vitro / animal model): A study investigated the antiphotoaging effect of standardized Piper retrofractum extract (PRE) on UVB-damaged human dermal fibroblasts and hairless mouse skin. PRE treatment activated PPARδ and AMPK, consequently upregulating mitochondrial synthesis and reducing ROS production. Additionally, PRE inhibited MMP expression via suppressing MAPK and AP-1. Oral administration of PRE at 300 mg/kg/day similarly regulated the signaling pathways and increased antioxidant enzyme expression, attenuating physiological deformations such as wrinkle formation and erythema response in mice.
Evidence strength: Preclinical (cell culture and hairless mouse model). No human clinical trials for antiphotoaging effects have been identified in the literature reviewed.
5.4 Antimicrobial Activity
Preclinical evidence (in vitro): A study investigated antimicrobial activities of crude bioactive metabolites extracted from fruits of P. retrofractum against 10 pathogenic organisms (bacteria and yeast) causing opportunistic infections in humans or animals, including Bacillus subtilis, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Vibrio parahaemolyticus, and Candida albicans. The disk diffusion test showed that the extract from methanol solvent exhibited greater antibacterial activity than other solvents, with inhibition zones ranging from 0.5 to 8.0 mm.
A separate study evaluated extracts of P. retrofractum fruits against bacterial pathogens including Staphylococcus albus, Salmonella typhi, Pseudomonas aeruginosa, Escherichia coli, Bacillus megaterium, and the fungus Aspergillus niger. Compared to streptomycin, all extracts exhibited good antibacterial activity, and some extracts also showed antifungal activity.
Evidence strength: In vitro only. No human clinical trials on antimicrobial applications of P. retrofractum have been identified.
5.5 Antileishmanial Activity
Preclinical evidence (in vitro and animal model): The n-hexane, ethyl acetate, methanol, and acetone extracts of P. retrofractum Vahl were evaluated in vitro against promastigotes of Leishmania donovani, and all exhibited significant in vitro activity at 100 μg/ml. From the extracts, (−)-sesamin, pellitorine, and piplartine were isolated. Piplartine showed significant antileishmanial activity in vitro at 100 μM and was further tested in vivo in a hamster model of visceral leishmaniasis, showing activity at 30 mg/kg dose. Amide piplartine isolated from a methanol extract of P. retrofractum showed good activity on Leishmania donovani with an IC₅₀ value of 7.5 µM.
Evidence strength: Preclinical (in vitro and hamster model). No human clinical trials have been conducted specifically on P. retrofractum for leishmaniasis.
5.6 Cytotoxic and Antiproliferative Activity
Preclinical evidence (in vitro): In a study of a combination extract with Zingiber officinale, while ginger contained terpenoids, Piper retrofractum contained alkaloid substances; the mixture showed cytotoxic activity against HeLa and T47D cancer cell lines with IC₅₀ values of 33 and 53 µg/mL respectively, causing cytotoxic effects through an apoptotic mechanism.
Based on studies of pharmacological activity, Javanese long pepper has been reported to have antimicrobial, antioxidant, cytotoxic, analgesic, androgenic, aphrodisiac, antihyperlipidemic, antihyperuricemic, leukocyte-count-lowering, antileishmanial, and immunostimulant effects.
Evidence strength: In vitro (cell line studies). No clinical oncology trials for P. retrofractum have been identified.
5.7 Neurotrophic and Neuroprotective Effects
Preclinical evidence (in vitro and animal model): In animal behavioral testing, the Barnes maze test showed that oral administration of pipernonaline in mice improved memory disorders induced by scopolamine and corticosterone. Three new compounds, together with 22 known compounds, were isolated from the fruits of Piper retrofractum; one compound was found to enhance the neurite outgrowth of NGF-mediated PC12 cells at concentrations ranging from 0.1 to 10 μM.
Evidence strength: Preclinical (in vitro and mouse model). No human clinical trials on neuroprotective effects of P. retrofractum have been identified.
5.8 Lymphedema and Lymphangiogenesis
Preclinical evidence (in vitro): Administration of Piper retrofractum extract has been reported to alleviate edema, but the mechanism was previously unknown. Promotion of lymphangiogenesis is known to improve lymphedema, and studies investigated whether PRE and specifically piperine can induce lymphangiogenesis. Treatments with PRE and piperine significantly promoted the proliferation, migration, and tube formation in human dermal lymphatic microvascular endothelial cells (HDLECs); furthermore, PRE and piperine significantly promoted the phosphorylation of AKT and ERK proteins in HDLECs.
Evidence strength: In vitro only. The report of edema alleviation is based on prior traditional observations and non-clinical data. No human clinical trials specifically on P. retrofractum for lymphedema have been identified.
5.9 Antitubercular Activity
Antitubercular biological activity of P. retrofractum has been reported in research articles. P. retrofractum has potential as an antitubercular agent, though evidence is limited to preclinical studies.
Evidence strength: Preclinical only. No human clinical trials on antitubercular applications have been identified.
5.10 Immunostimulant Activity
Clinical testing on P. retrofractum has been carried out in Indonesia, and the plant has shown potential to be developed into a traditional medicine of the phytopharmaceutical class. P. retrofractum has shown activity as an immunostimulant, which was found to be higher than the phytopharmaceutical immunostimulant group.
Evidence strength: Limited clinical data; primarily described in Indonesian regulatory and traditional medicine literature.
5.11 Antioxidant Activity
Isolated compounds from Piper retrofractum leaves showed modest α-glucosidase inhibitory (4.60±1.74% to 11.97±3.30%) and antioxidant activities under the tested conditions.
Evidence strength: In vitro only. Antioxidant activity is modest in these assays, and clinical relevance has not been established.
6. Body Systems and Health Areas Associated
- Digestive/Gastrointestinal system: The fruit is used in traditional medicine as an antiflatulent, expectorant, antifungal, antitussive, sedative, and anti-irritant, and for uterine contraction.
- Respiratory system: Dried fruits are used as an expectorant and antitussive in traditional medicines.
- Metabolic/Adipose tissue: Preclinical AMPK/PPARδ activation with effects on fat metabolism and body weight regulation in high-fat diet mouse models.
- Skin/Dermal system: Preclinical antiphotoaging effects via ROS reduction, collagen promotion, and MMP inhibition.
- Immune system: Immunostimulant activity has been demonstrated, reported as higher than that of a phytopharmaceutical immunostimulant comparator group.
- Neurological system: Preclinical neurite outgrowth promotion and memory improvement in mouse models.
- Lymphatic/Vascular system: Preclinical evidence for lymphangiogenesis and edema alleviation via AKT/ERK pathways.
- Reproductive system: Traditional use as aphrodisiac and for postpartum care; preclinical data on androgenic and aphrodisiac properties.
7. Dosage Forms and Dosages Reported in Studies
In the antiphotoaging mouse study, oral administration of PRE (standardized P. retrofractum extract) at 300 mg/kg/day was used in hairless mice to regulate signaling pathways and increase antioxidant enzyme expression, attenuating wrinkle formation and erythema response.
In the antileishmanial hamster model study, piplartine isolated from P. retrofractum showed activity at 30 mg/kg dose.
In a study on the aphrodisiac and toxicity effects of an infusion combining Piper retrofractum, Centella asiatica, and Curcuma domestica, administration of a high dose of 5,000 mg/200 g body weight of the infusion caused a significant difference in levels of SGOT and SGPT between pre- and post-treatment; the infusion at 1,000 mg/200 g body weight was found to have a safe aphrodisiac effect on male subjects.
No standardized human clinical dosages for Piper retrofractum as an isolated supplement have been established in peer-reviewed sources reviewed for this article. The vast majority of published dosages are from preclinical (animal or in vitro) studies only.
8. Safety Considerations and Interactions
General Toxicity
In the Thai traditional medicine literature, there has been no formal report of toxicity from long pepper. However, this observation is based on ethnobotanical use and limited laboratory evaluation rather than rigorous clinical safety trials.
Hepatotoxicity Signal at High Doses
In an animal study using an infusion of Piper retrofractum, Centella asiatica, and Curcuma domestica, administering a high dose (5,000 mg/200 g body weight) caused a significant difference in levels of SGOT and SGPT, indicating potential liver stress at high doses.
Piperine and Drug Interactions
In human and animal studies with single or short-term bolus application of isolated piperine, interactions with several drugs — in most cases resulting in increased drug bioavailability — were observed. Depending on the drug and extent of the interaction, such interactions may carry the risk of unintended adverse drug effects.
Reproductive and Antifertility Concerns
Animal studies with higher daily piperine bolus doses than those used in human interaction studies provide indications of disturbance of spermatogenesis and of maternal reproductive and embryotoxic effects. The antifertility activity of piperine was investigated in pregnant mice; piperine effectively inhibited implantation, produced abortion, and delayed labor when given from day 2 through day 5, day 8 through day 12, and day 15 until labor, respectively.
Traditional Ayurvedic Safety Note
In the Ayurvedic tradition, people with Pitta imbalance may find it hard to tolerate this spicy root; it may cause or worsen gastritis, burning sensation in the stomach, throat, palms, and feet.
Uterotonic Use in Traditional Medicine
In traditional medicine, the fruit of P. retrofractum has been used for uterine contraction, among other indications. This traditional indication, combined with the preclinical antifertility data from piperine studies, represents a notable safety consideration for use during pregnancy.
Evidence Gaps and Research Limitations
P. retrofractum has the potential for the treatment of several diseases and disorders, but there are only a few studies done to investigate the plant phytochemicals; further studies should be focused on isolation and identification of active compounds with pharmacological activities. Moreover, the majority of pharmacological studies have been performed using aerial parts of the plant, and further studies are needed to investigate bioactivity of other plant parts.
The literature study revealed the need for a thorough investigation of the pharmacological characteristics of the extracts and isolated compounds from P. retrofractum. Overall, the evidence base for P. retrofractum as a dietary supplement in humans remains predominantly preclinical (in vitro and animal models), with very limited formal human clinical trial data. Claims of specific health benefits in humans cannot currently be supported by the level of evidence available from the peer-reviewed literature.
References
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