Allspice is claimed to possess antimicrobial, antioxidant, anti-inflammatory, analgesic, antipyretic, anticancer, and antitumorigenic properties (Rompelberg et al. 1996; Al-Rehaily et al. 2002; Kluth et al. 2007). It contains a multitude of potential bioactive agents that may contribute to health promotion, including flavonoids, phenolic acids, catechins, and several phenylpropanoids (Al-Rehaily et al. 2002). Berries contain about 2-5% essential oils that include the following bioactive compounds: eugenol (60-75%), eugenol methyl ether, cineole (eucalyptol), phellandrene, and caryophyllenes (Kluth et al. 2007). The antioxidant and antimicrobial activities of allspice may be associated with eugenol (Rompelberg et al. 1996; Kluth et al. 2007).
Billing and Sherman (1998) reported that allspice was as effective as garlic and onions in suppressing microbial growth. The significance of its antimicrobial properties was recently highlighted by evidence that allspice and eugenol were effective in lowering the virulence of Escherichia coli O157:H7 (Takemasa et al. 2009). Nevertheless, there are concerns that allspice oil can be toxic and promote inflammation, nausea, and vomiting when consumed in excess.
The anticancer properties of allspice may be in part due to its ability to influence cytochrome P450 (CYP) activity and thereby influence carcinogen bioactivation. Kluth et al. (2007) cultured human liver carcinoma cells and human colon adenocarcinoma cells and studied the ability of the spice extract to activate mechanisms related to phase I detoxification enzymes. The allspice extract (3 mg/mL in dimethyl sulfoxide) did not activate pregnane X receptor (PXR) directly but did strongly activate the CYP3A4 promoter. Thus, the activation of transcription factors to bind to response elements seems like a plausible mechanism by which allspice, and potentially eugenol, function. There is specificity in the response to allspice and eugenol because gastrointestinal glutathione peroxidase (GPx), a phase II enzyme linked to removal of reactive oxygen species (ROS), was not influenced by allspice or eugenol (Kluth et al. 2007).
Inflammation is linked to increased risk of cancer (Dinarello 2010) and appears to be influenced by allspice consumption. Although controlled clinical interventions are not available, evidence in rodents suggests potency (Al-Rehaily et al. 2002). Providing an oral allspice suspension (500 mg/kg body weight) significantly inhibited carrageenan-induced paw edema and cotton pellet granuloma in rats. It also suppressed acetic acid-induced writhing and tail flick reaction time and decreased yeast-induced hyperpyrexia in mice. Interestingly, the suspension also appeared to have antiulcer and cytoprotective activity in rats by protecting gastric mucosa against indomethacin and various necrotizing agents, including 80% ethanol, 0.2 M sodium hydroxide (NaOH), and 25% sodium chloride (NaCl), suggesting that it might also have an impact on cyclooxygenase (COX) activity. It remains unclear what molecular target alteration(s) account for this response.
Evidence exists that allspice can alter the proliferation of several cultured cancerous cells. While cell viability was reduced about 50% when allspice extract was added to prostate cancer cells (LNCaP cells), it did not influence the viability of cultured human prostate cancer cell lines (DU145) or cervical epithelial carcinoma (HeLa) cells (Lee et al. 2007). The mechanism by which allspice leads to cellular growth depression remains largely unresolved. However, recent studies by Lee et al. (2007) suggest that epigenetics may be involved. A depression in histone acetyltransferase (HAT) activity may be involved. Androgen-induced HAT activity was decreased by 70% when allspice was provided at 100 μg/mL. Allspice also suppressed androgen receptor (AR) acetylation in LNCaP cells and significantly decreased histone H3 and H4 acetylation, indicating that a repression of AR-mediated transcription was induced due to shifts in histone and nonhistone acetylation. While these in vitro studies are intriguing, there is a need for controlled interventions in animal models before exploring allspice’s potential benefit as a dietary antitumorigenic agent.