Effect of Seasonal Variation on the Secondary Metabolites and Antioxidant Activity of Callistemon citrinus (Curtis) Skeels (Myrtaceae) Grown in Eastern Cape of South Africa

Abstract

Callistemon citrinus belong to the kingdom plantae, family Myrtaceae and genus Callistemon. It grows in Australia but has been naturalized in South Africa. It is used as traditional herb to combat both gastro-intestinal and respiratory diseases, pain, diseases caused by bacteria and fungi infection. About 500 g of the air-dried leaves were pulverized each month and subjected to hydro-distillation using a modified Clevenger apparatus. Hydro-distillation of the fresh leaves of C. citrinus gave a pale yellow volatile oil with a strong scenty fragrance, about 97 components were identified in the 12 treatments analyzed each month. The key components were pinocarvone (1.25-6.17 %), pinocarveol (0.10-9.56 %), α-terpineol (5.24-9.94 %), α-pinene (7.45-22.75 %), limonene (24.08) and eucalyptol (14.69-72.35 %). The compositional profile of the leaves of C. citrinus varied between (January-December). Treatments under investigation revealed markedly qualitatively and quantitatively differences. Antioxidant capacity of the volatile oil of C. citrinus leaves evaluated also demonstrated significance influence of seasonal variation on its activity. The most exigent activity for DPPH free radical scavenging was recorded in the month of September (spring) with an IC50 of 0.50 ± 0.04 mg mL-1, while the most paramount activity for the ABTS assay was 0.94 ± 0.02 mg mL-1 in January (summer).The lowest activity were observed in the June (winter) collection with IC50 of 1.45 ± 0.00 mg mL-1 and 2.19 ± 0.05 mg mL-1 for DPPH and ABTS assays, respectively. Results show that seasonal variations affected the chemical compositions, oil yield as well as antioxidant activities of the volatile oil of the leaves of (C. citrinus); therefore, it is important to consider such effects for industrial and therapeutic purposes.

Grasp of dihydroartemisinin resistance in Indonesia: Focused on genetic polymorphisms and new antimalarial

“…Natural products are considered promising reservoirs of potential candidates due to their wide array of chemical structures and biological effects [ 80 ]. The ethyl acetate and methanol extract of the Callistemon citrinus plant showed antiplasmodial activity with a half maximal inhibitory concentration (IC50) value of around 8.4–13.0 μg/mL [ 81 ]. Helianthus annuus roots also revealed antimalarial activity, proven through in vivo and in vitro tests by evaluating β-hematin levels, results reported to inhibit heme detoxification [ 82 ].…”

Comparative Studies of Essential Oil Composition and Biological Activities of Callistemon citrinus from Western Himalaya

“…Terpineol, α-Phellandrene and Limonene to be the major components of C. citrinus leaves EO. [2,3,9,[17][18][19][20] Twelve constituents representing 97.6 % of the EO were investigated from aerial part of C. citrinus. It also contained significant amount of α-Pinene (11.8 %) and 1,8-Cineole (75.9 %).…”

“…[7] C. citrinus is produced for decorative purposes in Mexico, and it has naturalized in South Africa, where it has been discovered to grow in practically every province. [8,9] In India, it is cultivated mostly for ornamental purposes but Netala and group (2015) reported that it is used for health benefits by the Indian ethnic tribal communities. [10] In Chinese traditional medicine it is used to cure haemorrhoids and gastrointestinal ailments.…”

Diverse continuous photooxygenation reactions of (+) and (−)-α-pinenes to the corresponding pinocarvones or trans-pinocarveols

“…5,6 Pine oils (also known as turpentine oil) are very convincing examples, being readily available from many different pine tree species planted in most parts of the planet; for the production of timber they also furnish in a non-destructive manner their essential oils. The major constituents are (+) and (−)-α-pinene (1a and b) and (−)-βpinene (1d), whose proportions vary according to the season, 7 geographic region, and pine species (Fig. 1), 8 and these molecules have a rich and well-established history of chemical transformations.…”

“…10 The photooxygenation reactions of (+)-α-pinene (1a) are well-known and yield different valuable products such as (−)pinocarvone (2a) 11 (Fig. 1) which is a much less abundant natural product 7 and can be considered a relevant building block for fine chemicals, chiral ligands, 12,13 polymers, 8 antimalarial peroxides, 14 and pheromones. 15 Usually, (−)-pinocarvone (2a) is obtained in batch processes, 11 but the protocol presents production risks, due to the formation of hydroperoxides as intermediates, making the scale-up unfeasible and with impacts on the production costs.…”