Seasonal variation on chemical composition and in vitro cytotoxic and anti-inflammatory activities of Myrciaria dubia (Kunth) McVaugh essential oil from Amazon

Abstract

Myrciaria dubia (Kunth) McVaugh is a fruit tree native to the Amazon, commonly known as camu-camu. This species has applications in traditional medicine, pharmaceuticals, and cosmetics due to its high content of phenolic compounds, such as anthocyanins and tannins in its fruits, which have antioxidant and anti-inflammatory properties. This work aims to evaluate the influence of seasonality on chemical composition, and in vitro cytotoxicity and anti-inflammatory activities of M. dubia essential oil. Botanical material was collected monthly, the leaf essential oils were extracted by hydrodistillation, and the fruits were subjected to simultaneous distillation-extraction. GC and GC-MS performed chemical analyses of the essential oils and volatile concentrates. The local climatic parameters insolation, temperature, relative humidity, and precipitation were monitored. The MTT assay was performed to evaluate cell viability. Subsequently, a nitrite standard curve was performed to determine the nitrite concentration in the samples. The oils were tested for cytotoxic activity against gastric ascites (AGP01), glioblastoma (AHOL), and lung cancer (A549) cell lines, as well as against non-malignant murine macrophages (RAW 264.7). The essential oil yield ranged from 0.4% (April/2024) to 0.9% (October/2023), with an annual average of 0.7 ± 0.1%. There were no significant differences in the yields of the dry and rainy periods. The leaf essential oils constituents were characterized by α-pinene (0.28–49.13%), (E)-caryophyllene (12.1–34.31%), caryophyllene oxide (4.03–17.08%), leptospermone (3.88–7.92%), and δ-cadinene (1.78–6.67%). The main compounds of fruit volatile concentrates were α-pinene (25.1–55.5%), α-terpineol (7.88–21.08%), limonene (6.43–16.79%), and (E)-caryophyllene (3.44–8.67%). The essential oils treatment of M. dubia seasonal study showed significant variations in the nitrite concentration, highlighting the oil's anti-inflammatory effect. The cytotoxic activity showed antiproliferative activity against cancer cell lines AGP01, AHOL, and A549, as well as non-malignant RAW 264.7. These results reinforce the value of M. dubia as a promising source for developing pharmaceutical ingredients, especially in combating inflammatory processes and cell therapy of tumor cell lines.