Adipose Tissue Accumulation ofd-Limonene With the Consumption of a Lemonade Preparation Rich ind-Limonene Content

Abstract

d-Limonene is a bioactive food component found in high concentration in citrus peel oil with anticancer effects in preclinical studies of mammary carcinogenesis. Extrapolation of preclinical data to human cancer is limited, in part, by inadequate information on the oral bioavailability and tissue disposition of d-limonene in humans. As a fat-soluble compound, d-limonene is more likely to deposit in fatty tissues such as the breast. To assess disposition of d-limonene in humans, we conducted a pilot study of oral d-limonene-rich lemonade. Following a 1-wk washout period devoid of citrus, healthy adults consumed 40 oz. of freshly prepared lemonade containing 500 to 600 mg d-limonene daily for 4 wk. On the first and last consumption days, blood and buttock fat biopsy were collected. Matched preintervention and postintervention fat biopsies (n = 7), and matched preintervention and postintervention plasma samples (n = 6), were analyzed for d-limonene levels using gas chromatography and mass spectrometry. There was a significant increase in d-limonene levels in the fat biopsies after 4 wk (P = 0.009); initial levels ranged from nondetectable to 7.79 μmol/kg tissue, and postintervention levels ranged from 53.6 to 294 μmol/kg tissue. Plasma d-limonene levels increased from 0.35 to 0.72 μmol/l initially to postintervention levels of 0.54 to 1.65 μmol/l (P = 0.016). Postintervention adipose d-limonene levels were 51.0 to 195 times higher than plasma levels (P = 0.009). Our results demonstrate accumulation of d-limonene in adipose tissue after oral dosing and support additional studies of d-limonene for chemoprevention in tissues such as the breast that are comprised of a significant fat fraction.

d-Limonene: a bioactive food component from citrus and evidence for a potential role in breast cancer prevention and treatment

“…Our results support the hypothesis that d-limonene accumulates in adipose tissue after oral dosing and also indicate the need for additional studies of d-limonene for chemoprevention in tissues like the breast that are composed of a significant fat fraction. Patient hematology and blood chemistry remained normal through the intervention [31]. Taken together, these preliminary results demonstrate that d-limonene is available in circulation for deposition in adipose tissue.…”

“…The dose-limiting toxicities and failure to achieve any anti-tumor activity in vivo largely led to a decline in interest in this agent in the treatment and prevention setting where the toxicities unacceptably outweigh in potential benefit for anti-cancer effects acting earlier in the preneoplasia state. In contrast, d-limonene is a hydrophilic compound with similar anticancer properties that exhibit distinct metabolism and disposition largely depositing in adipose tissue with low toxicity in the oral form [21,31]. Table 2 summarizes our work demonstrating that after healthy adults consume 500 mg d-limonene daily from lemonade for 4 weeks, d-limonene adipose tissue levels accumulate to 120-fold that of plasma [31].…”

“…None of these studies indicate a signaling mechanism that would explain the increase in immune response after Adapted from Miller et al [31] a N = 7 b N = 6 c Initial adipose and plasma levels were not significantly different (P = 0.33) d Significantly higher than the initial adipose samples (P = 0.009) e Post-4 week intervention adipose levels were significantly higher than plasma levels (P = 0.009) f Significantly higher than the initial plasma samples (P = 0.016) d-limonene treatment. Host immune response is important for resistance to many types of cancer, including breast, and new cancer therapies that activate an immune response are in development [37,38].…”

“…In contrast, d-limonene is a hydrophilic compound with similar anticancer properties that exhibit distinct metabolism and disposition largely depositing in adipose tissue with low toxicity in the oral form [21,31]. Table 2 summarizes our work demonstrating that after healthy adults consume 500 mg d-limonene daily from lemonade for 4 weeks, d-limonene adipose tissue levels accumulate to 120-fold that of plasma [31]. Therefore, a lower dose of d-limonene may be sufficient to achieve comparable steady-state therapeutic levels at the tissue level compared to high doses of perillyl alcohol without the associated toxicities.…”

Plasma Metabolomic Profiles of Breast Cancer Patients after Short-term Limonene Intervention

“…The underwhelming results of these trials reduced enthusiasm for limonene development. Unlike perillyl alcohol, limonene distributes favorably to adipose tissue in rodents [18, 19] and humans [20] resulting in tissue levels comparable to the active concentrations in preclinical models. Favorable distribution of limonene to adipose tissue suggests that evaluation of limonene’s potential clinical activity deserves further attention, particularly within the context of cancers arising from organs with high adiposity such as breast.…”