Stenocalyx (Eugenia) EO

Essential oil from Eugenia dysenterica leaves was able to inhibit both the diarrhoea and enteropooling induced by castor oil; however, the distance travelled by charcoal meal in the intestine was not change. These data suggest that the antidiarrhoeic effect of the essential oil from E. dysenterica leaves is related to its ability to inhibit intestinal secretion and/or to increase intestinal absorption.

Identification

Botanical name: Eugenia uniflora L. (syn. Stenocalyx michelii O. Berg, Eugenia michelii (O. Berg) Legr.).

Family: Myrtaceae.

Common names: Pitanga, Brazilian cherry, Surinam cherry, Cayenne cherry.

Plant part used: Leaves (primarily); occasionally fruits or flowers.

Note: The genus Stenocalyx has been largely incorporated into Eugenia. This monograph focuses on E. uniflora, the species most commonly associated with “Stenocalyx” references in essential oil literature.

Origin and Habitat

Native to South America (primarily Brazil, but extending to Uruguay, Paraguay, and northern Argentina). Widely cultivated in tropical and subtropical regions worldwide for its edible fruit. It grows as a shrub or small tree in humid forests, coastal areas, and disturbed sites.

Production Method

Obtained by steam or hydrodistillation of fresh or dried leaves. Yields are typically low to moderate (0.1–0.5% or higher depending on material and conditions). Production is mainly small-scale or research-oriented in Brazil and other producing countries.

Physical Characteristics (Typical Ranges)

• Appearance: Clear to slightly viscous mobile liquid.
• Color: Pale yellow to yellowish-green or amber.
• Odor: Characteristic herbaceous, spicy, fruity-sweet with floral, terpenic, and slightly medicinal notes; reminiscent of the crushed leaves of the pitanga plant.
• Relative density (d₂₀²⁰): Approximately 0.880–0.920 (typical for sesquiterpene-rich oils).
• Refractive index (n_D²⁰): Approximately 1.490–1.510.
• Optical rotation (α_D²⁰): Usually levorotatory.
• Solubility: Soluble in alcohol and fixed oils; insoluble in water.

Physical constants show natural variation and should be verified by batch-specific Certificates of Analysis.

Chemical Composition / Chromatographic Profile

Eugenia uniflora leaf oil is predominantly sesquiterpene-rich with significant chemical variability (multiple chemotypes reported). No single ISO standard exists, but profiles are analyzed per GC-MS methods (e.g., ISO 11024 principles).Major components (representative ranges from key studies):

• Curzerene: Up to 47% (common major component in many samples).
• Germacrone: 4–65% (dominant in some chemotypes).
• γ-Elemene / Germacrene B / Bicyclogermacrene: Often 5–20%.
• Selina-1,3,7(11)-trien-8-one (and its epoxide): Significant in certain chemotypes (up to 18–29%).
• Furanodiene / other furanosesquiterpenes: Characteristic markers.
• Other notables: β-caryophyllene, caryophyllene oxide, spathulenol, α-pinene/limonene (in monoterpene chemotypes).

Typical chemotypes:

• Curzerene/germacrone-rich (most reported).
• Selina-triene-one-rich.
• Variable sesquiterpene hydrocarbon profiles.

Over 30–50 compounds are typically identified, with sesquiterpenes (hydrocarbons and oxygenated) often comprising 70–95% of the oil. Composition varies greatly with genotype, origin, harvest season, and plant part.

Storage and Stability

Store in tightly sealed, preferably dark glass containers, protected from heat, light, and air. Shelf life is typically 1–3 years under cool conditions. Sesquiterpenes are relatively stable, but monitor for oxidation.

Uses and Properties (Summary)

Traditionally used in Brazil for digestive issues, fever, hypertension, and as an anti-inflammatory. In modern applications: aromatherapy, natural perfumery, cosmetic formulations, and research into antimicrobial, antioxidant, anti-inflammatory, antiparasitic (e.g., anti-Leishmania), and cytotoxic activities. The oil shows potential for food preservation and therapeutic exploration due to its sesquiterpene content.

Safety and Precautions

• Generally considered mild but data are limited compared to major commercial oils.
• Potential skin sensitizer/irritant in undiluted form; always dilute for topical use and perform patch tests.
• Avoid undiluted application, eyes, and mucous membranes.
• Use with professional guidance during pregnancy, breastfeeding, or with young children.
• Some studies indicate cytotoxicity in high concentrations (research context).
• Refer to current SDS and regulatory guidelines. Not widely regulated under IFRA or pharmacopoeial monographs.

References and Analytical Methods

• GC-MS and retention indices (aligned with ISO 11024).
• Key literature: Apel et al. (sections on Stenocalyx), Rodrigues et al. (2013), Cipriano et al. (chemical variability), Ogunwande et al., and various Brazilian Myrtaceae studies.

This monograph compiles factual information from scientific sources. Eugenia uniflora essential oil exhibits high chemical polymorphism; for any commercial, regulatory, or therapeutic use, rely on batch-specific analysis and current safety data. No dedicated ISO standard currently exists for this oil.

Antidiarrhoeic effect of Eugenia dysenterica DC (Myrtaceae) leaf essential oil

Essential Oils from *Eugenia* Species—Part VII: Sections Phyllocalyx and Stenocalyx