Cubeb

Synopsis

Cubeb (Piper cubeba L.f.)

Identity and Botanical Overview

Taxonomy and Nomenclature

Piper cubeba is a perennial evergreen climbing shrub in the Piperaceae family, native to Southeast Asia, particularly Indonesia and Malaysia, where it grows up to 6 meters in length on supporting vegetation. Also called tailed pepper or Java pepper, it belongs to the Domain Eukaryota, Kingdom Plantae, Division Magnoliophyta, Class Magnoliopsida, Order Piperales, and Family Piperaceae. As part of the genus Piper, which encompasses approximately 2,000 species of predominantly tropical shrubs, herbs, and lianas, P. cubeba is phylogenetically close to Piper nigrum, the black pepper plant, sharing similar inflorescence structures and ecological niches within the Piperaceae family.

The name cubeb comes from Arabic kabāba (كبابة) by way of Old French quibibes. Common names for P. cubeba include tailed pepper and Java pepper in English, reflecting its distinctive fruit morphology and primary region of cultivation, as well as kabab chini in Hindi, meaning "Chinese cubeb." The full binomial authority is Piper cubeba L.f. (Linnaeus filius), distinguishing it from the closely related Piper nigrum.

Botanical Description

This climbing plant grows up to ten meters, with dark green, leathery leaves as much as 15 cm in length. The cubeb pepper plant possesses inconspicuous white flowers. The female flowers later develop into round, soft berries with a fruit diameter of five mm. They have a slightly wrinkled surface and a stem about one cm long, and these small peppers possess the distinguishing feature of a small tail or stem. The plant features dioecious flowers arranged in spikes and produces small, drupe-like fruits that remain attached to the peduncle even when mature, giving them a distinctive "tailed" appearance.

Geographic Distribution and Cultivation

Cubeb is a widespread and cultivated plant, especially in Indonesia (mainly in Java and Sumatra), but also in other parts of the tropics, for its use as a medicinal plant, seasoning and source of an essential oil. It is cultivated mainly in Indonesia on Java and Sumatra, often as a secondary crop in coffee plantations. Piper cubeba inhabits Java, Prince of Wales Island, Sumatra, Southern Borneo, and other isles in the Indian Ocean, growing without cultivation in the forests. They are also cultivated to some extent in the coffee plantations of Java, being easy to grow when placed so as to climb the shade trees which are necessary in a coffee plantation.

Harvest and Commercial Forms

The fruits are harvested immature, dried, and used primarily as a spice due to their bitter, pungent taste and aromatic odor. Commercial cubebs consist of the dried berries, similar in appearance to black pepper, but with stalks attached — the "tails" in "tailed pepper." The dried pericarp is wrinkled, and its color ranges from grayish-brown to black. The seed is hard, white and oily. The odor of cubebs is described as agreeable and aromatic, and the taste as pungent, acrid, slightly bitter and persistent.

Cubeb is sold as whole dried berries, ground powder, or essential oil. Cubeb is also marketed as a refreshing agent and used in various products such as chewing gums, alcoholic and soft drinks, sherbets, gelatin confectionery, and toothpaste. Cubeb is used to flavor alcoholic and non-alcoholic drinks such as Bombay Sapphire gin and Pertsovka, a Russian pepper vodka which is prepared from a cubeb infusion.

Traditional and Historical Use

Origins and Spread Through Trade

It has been cultivated throughout the world and used for thousands of years for food flavoring, in traditional medicines, and essential oil applications. Cubeb came to Europe via India through the trade with the Arabs. Cubeb was introduced to Arabic cuisine around the 10th century. The Travels of Marco Polo, written in the late 13th century, describes Java as a producer of cubeb, along with other valuable spices.

In the Tang dynasty, cubeb was brought to China from Srivijaya. In India, the spice came to be called kabab chini, that is, "Chinese cubeb," possibly because the Chinese had a hand in its trade, but more likely because it was an important item in the trade with China.

Ayurvedic and Indian Traditional Medicine

In India, Sanskrit texts included cubeb in various remedies. Charaka and Sushruta prescribed a cubeb paste as a mouthwash, and the use of dried cubebs internally for oral and dental diseases, loss of voice, halitosis, fevers, and cough. Cubeb pepper has always played a central role in traditional Indian medicine (Ayurveda). Ayurveda values cubeb pepper as a spice, cosmetic, and medicine. In India, many families produce their own remedies according to their own recipes, which are passed down from generation to generation.

Unani and Islamic Medicine

Physicians in the Islamic Golden Age distilled "water of al butm" (turpentine) from a mixture of herbal products, including cubeb. Unani physicians described cubeb (kabab chini) as possessing properties including Mudirre baul (diuretic), Mufattit wa Mukhrije Hasat (lithotriptic), Dafeye taffun (antiseptic), Muqawwiye Kulyah (kidney tonic), and Mohafize Kulyah (nephroprotective), as cited by Ibn Sina, Razi, and Ibn-e-Baitar. Unani physicians also used a paste of the cubeb berries externally on male and female genitals to intensify sexual pleasure during coitus. Due to this attributed property, cubeb was called Habb-ul-Uruus.

Tibetan Medicine

In Tibetan medicine, cubeb (ka ko la in Tibetan) is one of bzang po drug, six fine herbs considered beneficial to specific organs in the body, with cubeb assigned to the spleen.

Traditional Chinese Medicine

In traditional Chinese medicine, cubeb is used for its alleged warming property. In China, this pepper was called both vilenga and viḍaṅga (the cognate Sanskrit word), and the Chinese name is 荜澄茄 (bì chéng qié).

Medieval European Use

A patent of pontage granted in 1305 by Edward I, to aid in repairing and sustaining the Bridge of London, authorizing toll on various articles, mentions among groceries and spices, cubebs as liable to impost. Cubebs occur in the German lists of medicines of Frankfurt and Nördlingen, about 1450 and 1480; they are also mentioned in the Confectbuch of Hans Folcz of Nuremberg, dating about 1480. In medieval Europe, Paracelsus (1493–1541) thought of cubeb pepper as a "warming spice" and attributed to it a life-prolonging effect.

In his Theatrum Botanicum, John Parkinson tells that the king of Portugal prohibited the sale of cubeb to promote black pepper (Piper nigrum) around 1640. After the prohibition of its sale in Portugal in 1640, culinary use of cubeb decreased dramatically in Europe, and only its medicinal application continued to the 19th century.

Victorian and 19th-Century Medical Use

In Victorian and Edwardian England, cubeb was an antiseptic for gonorrhea treatment. William Wyatt Squire wrote in 1908 that cubeb berries "act specifically on the genitourinary mucous membrane. (They are) given in all stages of gonorrhea," and The National Botanic Pharmacopoeia printed in 1921 stated that cubeb was "an excellent remedy for flour albus or whites." It experienced a brief resurgence in 19th-century Europe for medicinal uses, but has practically vanished from the European market since.

Culinary Uses Across Cultures

In Moroccan cuisine, cubeb appears in savory dishes and pastries like markouts, and it is one of the key ingredients in ras el hanout, the iconic spice blend used across the Middle East and North Africa. Medieval European cooks also used cubeb regularly, though it fell out of fashion in Western kitchens by the 17th century. In Indonesian cuisine, especially in Indonesian gulés (curries), cubeb is frequently used.

Traditionally, P. cubeba is used for the treatment of gonorrhea, dysentery, syphilis, abdominal pain, diarrhea, enteritis, and asthmatic diseases.

Phytochemistry: Key Constituents and Active Compounds

Overview of Chemical Classes

The biological activities of P. cubeba are attributed to its phytochemicals — phenolic compounds, lignans, and alkaloids — and to the essential oil of the plant. It contains a considerable group of essential oils, polyphenolic compounds, alkaloids and other phytochemical constituents which possess pharmacological activities such as antimicrobial, antioxidant, anti-inflammatory, hepatoprotective, nephroprotective, gastroprotective, and diabetic control properties.

Lignans

According to current investigations, lignans are the main active constituents of the plant, in which cubebin is the most abundant. From Piper cubeba, lignans of several classes can be isolated from the roots, rhizomes, stems, leaves, seeds, and fruits. Among its various chemical constituents, (−)-cubebin and (−)-hinokinin are found in significant quantities. Although they have been known for some time, during the last few decades their biological properties have been studied by several research groups.

Cubebin (C₂₀H₂₀O₆) is a crystalline organic compound isolated from cubeb oilcake, and can be chemically synthesized from cubebene. It was discovered by Eugène Soubeiran and Hyacinthe Capitaine in 1839, and irritates the mucous membranes. The plant is also a rich source of lignans, particularly cubebin, a bioactive compound with a wide range of biological activities such as antimicrobial, anticancer, and neuroprotective, among others.

Essential Oil

A high proportion of up to 10% essential oils, mainly monoterpenes and sesquiterpenes, gives the cubeb its characteristic woody-bitter taste. A total of 36 volatile compounds were identified in the essential oil, with Z-isoeugenol, dihydroeugenol, β-pinene, E-caryophyllene, and 1,8-cineole as major constituents. The precise composition of the essential oil varies considerably by geographic origin and extraction method. Using GC–MS, principal components in one chemotype were identified as methyleugenol (41.31%) and eugenol (33.95%), followed by (E)-caryophyllene (5.65%), p-cymene-8-ol (3.50%), 1,8-cineole (2.94%), and α-terpinolene (1.41%).

These differences in composition might be attributed to the different extraction methods, detection techniques, as well as geographic distribution and genetic chemotypes.

Other Notable Constituents

Cubeb mainly contains cubebic acid, cubeb-resin, volatile oil, cubebin, and fatty oil. The more important constituents of cubebs are: volatile oil, fatty oil, cubebin, cubebic acid, and indifferent cubeb-resin, the latter two substances alone carrying the diuretic qualities of the drug. Calcium and magnesium malates are also present. The berries were found to be rich in sodium and iron, with moderate zinc content. Amino acid analysis revealed a considerable concentration of isoleucine and phenylalanine, whereas 11,14,17-eicosatrienoic acid and linoleic acid were identified as the major fatty acids.

The two peppers (cubeb and black pepper) are different in composition; for example, black pepper contains piperidines absent in cubeb.

Mechanisms of Action

Anti-Inflammatory Mechanisms

A 2019 in vitro study elucidated the anti-inflammatory mechanism of P. cubeba methanol extract (Pc-ME) by focusing on NF-κB signaling. Cellular activity and molecular targets were identified in macrophage RAW264.7 cells and HEK293T cells. Pc-ME reduced NO production without any cell toxicity; inhibited expression of proinflammatory cytokines such as iNOS and IL-6; downregulated NF-κB activation mediated by both MyD88 and TRIF; and diminished the phosphorylation of IκBα, IKKα/β, Akt, p85, Src, and Syk. Pc-ME inhibited Syk and Src autophosphorylation during overexpression in HEK cells, which confirmed that Syk and Src were signaling targets of Pc-ME. These findings indicate that Piper cubeba L. has anti-inflammatory activity by targeting Src/Syk in the NF-κB pathway.

Cubebin, the principal lignan of P. cubeba, has been shown — in animal studies — to exhibit significant anti-inflammatory activity using the carrageenan-induced paw edema model in rats, but did not provide a significant reduction in cell migration for the acute carrageenan-induced inflammatory reaction in the peritoneal cavity. Neither was it effective in reducing the edema induced by dextran nor the edema induced by histamine. It partially reduced the edema induced by serotonin. Moreover, it significantly reduced the edema induced by prostaglandin PGE₂ and the number of writhings induced by both acetic acid and PGI₂ in mice. It was therefore suggested that the mechanism of action of cubebin is similar to that observed for most non-steroidal drugs.

Antioxidant Mechanisms

Studies of one chemotype showed antioxidant activity via DPPH radical scavenging (IC₅₀ = 110.00 ± 0.08 μg/mL), as well as potent antioxidant activity against both ferric reducing/antioxidant power (FRAP) (106.00 ± 0.11 μg/mL) and β-carotene bleaching (IC₅₀ = 315.00 ± 2.08 μg/mL) assays, when compared to the positive controls butylated hydroxytoluene and ascorbic acid. These effects can be attributed to the presence of terpenes, as well as the phenolic compounds that significantly enhance free radical scavenging activity.

Intracellular Signaling and Gene Regulation

The most reported modes of action by which P. cubeba extracts exert their biological activities involve many intracellular targets, among them the regulation of gene expression, inhibition of oxidative stress, induction of apoptosis, and quorum sensing inhibition.

Scientific Evidence by Area of Use

1. Antimicrobial Activity

Evidence type: Animal and in vitro studies.

A study was designed to investigate the possible antinociceptive, antipyretic and antimicrobial activities of the essential oil obtained from the fruits of Piper cubeba. To assess the antinociceptive and antipyretic activities, three doses (150, 300 and 600 mg/kg, i.p.) were tested in acetic acid-induced abdominal writhing, tail-flick reaction, hot-plate, and brewer's yeast-induced hyperpyrexia test models in animals. Moreover, antimicrobial activity was examined using agar diffusion method and broth micro-dilution assay for minimum inhibitory concentrations (MIC). The essential oil showed marked antinociception (17, 30 and 54%) and an increase in reaction time in the tail-flick and hot-plate tests. The brewer's yeast-induced hyperpyrexia was decreased in a dose-dependent manner. The essential oil also exhibited a strong antimicrobial potential. These findings were described as confirming the traditional analgesic indications of P. cubeba oil and as supporting its use in Arab traditional medicine.

It has been reported that Piper cubeba is a potential medicinal plant that has various phytochemicals and its uses in antimicrobial, anti-inflammatory, antibacterial, antioxidant, anti-cancerous, hepatoprotective, nephroprotective, and antileishmanial activity. No controlled human clinical trials investigating the antimicrobial efficacy of cubeb preparations have been identified in the peer-reviewed literature.

2. Anti-Inflammatory Activity

Evidence type: In vitro and animal studies only. No human clinical trials identified.

A published study found that Piper cubeba L. is a plant that acts as an antioxidant and anti-inflammatory agent. However, the molecular mechanism of the anti-inflammatory activity had not been fully investigated at the time. The study elucidated the anti-inflammatory mechanism by focusing on NF-κB signaling, which is considered a prototypical inflammatory signaling pathway in both innate and adaptive immune functions. This research was conducted entirely in cell culture models (RAW264.7 macrophages and HEK293T cells), not in humans.

Laboratory studies have identified anti-inflammatory, antimicrobial, and antioxidant activity in cubeb extracts, which aligns with the berry's long history in traditional medicine. However, most of this research has been conducted in cell cultures or animal models rather than in human clinical trials, so the strength of these effects in people remains unclear.

3. Antioxidant Activity

Evidence type: In vitro studies. No human clinical trials identified.

In the DPPH and FRAP assays, the water extract of P. cubeba elicited considerable antioxidant activity compared to reference compounds. Enzyme inhibitory assays revealed that the essential oil had a potential to inhibit tyrosinase and elastase enzymes with IC₅₀ values of 340.56 and 86.04 μg/mL, respectively. These results are from laboratory assays and have not been validated in human subjects.

4. Anticancer Activity

Evidence type: In vitro cell line studies only. No animal or human clinical trials confirmed for cubeb specifically as an anticancer treatment.

A study aimed to evaluate the cytotoxicity of a crude extract of Piper cubeba against normal and breast cancer cell lines. To prepare the extract, P. cubeba seeds were ground, soaked in methanol and dichloromethane and isolated by column chromatography. The results showed that the methanolic crude extract had higher cytotoxic activity against MDA-MB-468 and MCF-7 breast cancer cell lines than a dichloromethane crude extract. The methanolic crude extract was then separated into six fractions; Fraction C was highly active against breast cancer cell lines with an IC₅₀ value less than 4 μg/mL.

Fraction CE demonstrated the highest activity against MCF-7 cells with an IC₅₀ value of 2.69 ± 0.09 μg/mL and lower cytotoxicity against normal fibroblast L929 cells with an IC₅₀ value of 4.17 ± 0.77 μg/mL. DNA fragmentation with a ladder pattern characteristic of apoptosis was observed in MCF-7, MDA-MB-468, MDA-MB-231 and L929 cells, but not in MCF-12A (normal breast) cells. The results suggested that Fraction CE had a cytotoxic effect on breast cancer cell lines, and its mechanism of action appeared to include the induction of apoptosis. These are preliminary in vitro findings and cannot be extrapolated to clinical cancer treatment without human trials.

5. Antiparasitic Activity

Evidence type: In vitro and limited in vivo (animal) studies.

Essential oil of P. cubeba fruits inhibited the survival of T. cruzi promastigotes with an IC₅₀ of 45.5 μg/mL and amastigotes with an IC₅₀ value of 87.9 μg/mL. Cubebin, dihydrocubebin, and hinokinin isolated from the fruits exhibited ovicidal activities against fecal isolates of both Haemonchus contortus and Trichostrongylus sp., with EC₅₀ values of 150, 186.7, and 68.3 μg/mL, respectively. Hinokinin, cubebin, yatein, and 5-methoxyyatein from the fruits at the concentration of 50 μM inhibited the motility of S. mansoni by 75%, 75%, 75%, and 100%, respectively.

Cubebin exhibited significant in vitro antileishmanial activity at 100 μM. An in vivo experiment carried out in golden hamsters against L. donovani amastigotes showed that cubebin slightly reduced parasitic burden and spleen weight. These results are preliminary and require further investigation.

6. Genitourinary Applications

Evidence type: Historical pharmacopeial record and traditional use; no modern controlled clinical trials identified.

The diuretic qualities of the drug were historically attributed to cubebic acid and cubeb-resin specifically. The main medicinal uses for cubeba have historically related to genitourinary infections such as remedies for gonorrhea, cystitis, urethritis, abscesses of the prostate gland, and to treat leucorrhoea. These applications derive from traditional use rather than from prospective clinical trial evidence. No rigorous human trials in the modern pharmacological literature were identified for these indications.

7. Respiratory System

Evidence type: Traditional use with limited preclinical support; no human clinical trials identified.

Piper cubeba is a popular traditional herbal medicine used for the treatment of many diseases, especially digestive and respiratory disorders. It has been attributed with the ability to stimulate the secretions of the pulmonary and urinary apparatus. These claims rest primarily on centuries of traditional practice in Ayurveda and Unani medicine, with no controlled human trials identified that test these effects.

8. Dermacosmeceutical Activity

Evidence type: In vitro, with computational modelling. No human studies identified.

The potent antioxidant, anti-inflammatory, and antimicrobial properties of the extracts and essential oil derived from P. cubeba make the plant's ingredients potentially suitable for application in the skincare and cosmetic industries. However, there has been very limited research conducted on the plant's effects in dermatology and cosmetics. Enzyme inhibitory assays revealed that the essential oil had a potential to inhibit tyrosinase and elastase enzymes with IC₅₀ values of 340.56 and 86.04 μg/mL, respectively. These findings are strictly in vitro.

9. Nephroprotective and Hepatoprotective Activity

Evidence type: Animal studies only.

Different extracts from the plant have demonstrated antioxidant, antimicrobial, nephroprotective, hepatoprotective, and anti-inflammatory activities. These findings are primarily from animal and cell-culture studies. No human clinical data were found in the reviewed literature to confirm these effects.

Overall Assessment of Evidence Quality

There is no systematic data regarding the pharmacokinetics and clinical research of P. cubeba. Therefore, there is not enough evidence to interpret the specific mechanisms for the observed biological activities. Several studies have shown that P. cubeba extracts, essential oils, and their constituents are endowed with many biological and pharmacological properties such as antioxidant, anti-inflammatory, antidiabetic, anticancer, reno-hepatoprotective, immunomodulatory, antidepressant, antimicrobial, anti-parasite, insecticidal, wound healing, and antidepressant activities. However, the overwhelming majority of this research has been conducted in cell lines, microbial assays, or rodent models. No large-scale randomized controlled human clinical trials for any therapeutic indication have been reported in the peer-reviewed literature as of the date of this article. Evidence for most claimed benefits of cubeb should therefore be characterized as preliminary, largely preclinical, and in need of clinical validation.

Dosage Forms and Doses Reported in Research

No standardized dosage for human therapeutic use has been established. The following doses appear in the cited preclinical research:

Three doses of the essential oil (150, 300, and 600 mg/kg, i.p.) were tested in animal models of antinociception, antipyrexia, and antimicrobial activity.
Male Wistar rats subjected to treatment by P. cubeba essential oil at doses ranging from 50 to 3,000 mg/kg showed no mortality nor overall behavioral alteration.
In vitro, Fraction C of a methanolic seed extract was highly active against breast cancer cell lines with an IC₅₀ value less than 4 μg/mL.
Fraction CE of the same extract demonstrated the highest activity against MCF-7 cells with an IC₅₀ value of 2.69 ± 0.09 μg/mL.
Hinokinin, cubebin, yatein, and 5-methoxyyatein from the fruits at a concentration of 50 μM inhibited the motility of S. mansoni by 75%, 75%, 75%, and 100%, respectively.

These figures are drawn from in vitro and animal studies and are not directly applicable to human dosing.

Safety Considerations

Preclinical Toxicology Data

In vivo, female Wistar rats fed with the methanol extract of P. cubeba fruits were safe up to a maximum dose of 2,000 mg/kg body weight. It induced neither changes in behavioral patterns nor signs and symptoms of toxicity nor mortality. In another study, (−)-hinokinin, obtained by partial synthesis from (−)-cubebin isolated from the fruits of P. cubeba, was orally administered (1 mL/rat) to male Wistar rats daily for 1 week. This treatment did not cause any significant weight or water intake changes during the period of the experiment.

Using the MTT assay, P. cubeba extracts were not toxic to RAW 264.7 cells. In addition, normal oral fibroblasts treated with P. cubeba-based compounds — mainly methylcubebin, dihydrocubebin, and hinokinin — showed neither cytotoxicity signs nor morphological changes.

Limitations of Available Safety Data

Limited peer-reviewed research specifically addresses cubeb oil safety. Published literature focuses primarily on chemical composition analysis and traditional medicinal uses rather than comprehensive toxicology studies. The lack of published adverse event data, combined with its historical use, suggests an acceptable safety margin for typical flavoring applications at low concentrations. Further research would enhance the scientific understanding of cubeb oil's safety profile, particularly regarding long-term exposure at various dietary levels. The absence of such studies reflects both the ingredient's traditional background and its relatively limited modern use in Western food systems.

Genotoxicity and Cell-Level Toxicity Notes

Plant constituents can interact with biological components in cells such as proteins and nucleic acids; therefore, toxicity studies are mandatory to ensure the beneficial and biosafety effects of the tested materials. One study assessed the safety profile of (−)-cubebin by testing its cytotoxicity, mutagenicity, cell proliferation kinetics, and induction of apoptosis in human colon adenocarcinoma cells (HT29). The MTT assay showed that (−)-cubebin was cytotoxic at 280 μM, whereas no cytotoxicity was demonstrated below 28 μM. This concentration-dependent effect underscores the importance of dose in safety considerations for isolated cubebin.

Historical Note on Adulteration

Cubeb pepper has not to be confused with the false cubeba (P. crassipes), commonly used to adulterate cubeba aromatic mixtures. Adulteration of cubeb preparations remains a historical concern, first noted in medieval Europe.