Antioxidant and antibacterial activities of red (Hylocereus polyrhizus) and white (Hylocereus undatus) dragon fruits

Abstract

Dragon fruit belongs to the genus Hylocereus of the Cactaceae family. There are two species that are commonly cultivated; Hylocerues polyrhizus and Hylocereus undatus that have the same red skin but different flesh colours, red and white respectively. Although from the same genus, the phytochemical contents and bioactivities of both fruits may not be the same. This study aims to compare the phytochemical contents, antioxidant and antibacterial activities of H. polyrhizus and H. undatus to help consumers better choose nutritional fruits and to explore potential natural preservatives. The fruit samples were extracted using 50% ethanol and later were subjected to phytochemical, antioxidant and antibacterial assays. The phytochemical contents were determined using Folin Ciolcalteu and aluminium chloride methods for total phenolic and total flavonoid respectively. The antioxidant activity was determined using diphenyl-picryl hydrazine (DPPH) and 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. Disk diffusion method was performed to evaluate antibacterial activities against two food-borne pathogens, Escherichia coli and Staphylococcus aureus. H. polyrhizus showed to contain significantly higher phenolic content (p<0.05), while H. undatus had significantly higher flavonoid content (p<0.05). Comparison of antioxidant activities in both fruit samples indicated higher activities were observed in H. polyrhizus and both fruit extracts showed inhibition zones against the tested bacteria with H. polyrhizus extract was able to inhibit at lower concentration. The results suggest that H. polyrhizus may have higher bioactivities compared to H. undatus due to the significantly higher phenolic content.

Nutrition Value of Baked Meat Products Fortified with Lyophilized Dragon Fruit (Hylocereus undatus)

“…Dragon fruit (pitaya) is a tropical fruit belonging to the Cactaceae family, genus Hylocereus. There are mainly three commercial varieties distinguished by the color of their skin and flesh: Hylocereus undatus (red skin and white flesh), Hylocereus polyrhizus (red skin and red flesh), and Hylocereus megalanthus (yellow skin and white flesh) [3]. Dragon fruit is considered one of the "superfoods" due to its richness in nutrients and relatively low caloric content.…”

Review: Studi Kandungan Fitokimia dan Aktivitas Antibakteri Tanaman Buah Naga (Hylocereus spp.)

“…Selain itu, ekstrak etanol juga efektif melawan S. aureus (⌀14,7 ± 1,15 mm) dan S. epidermidis (⌀ 8,1 ± 0,17 mm) [40]. Zakaria et al (2022) yang melaporkan ekstrak etanol 50% buah naga merah dan putih terhadap pertumbuhan bakteri E. coli dan S. aureus, menyatakan bahwa ekstrak menghasilkan zona hambat pada konsentrasi 0,5 g/ml terhadap bakteri Gram negatif (E. coli) sedangkan terhadap bakteri Gram positif (S. aureus) ekstrak mampu menghambat pada konsentrasi 100,5 g/ml. Sehingga ekstrak etanol 50% buah naga merah dan putih lebih baik dalam menghambat pertumbuhan bakteri Gram negatif dengan konsentrasi yang lebih kecil [41].…”

“…Zakaria et al (2022) yang melaporkan ekstrak etanol 50% buah naga merah dan putih terhadap pertumbuhan bakteri E. coli dan S. aureus, menyatakan bahwa ekstrak menghasilkan zona hambat pada konsentrasi 0,5 g/ml terhadap bakteri Gram negatif (E. coli) sedangkan terhadap bakteri Gram positif (S. aureus) ekstrak mampu menghambat pada konsentrasi 100,5 g/ml. Sehingga ekstrak etanol 50% buah naga merah dan putih lebih baik dalam menghambat pertumbuhan bakteri Gram negatif dengan konsentrasi yang lebih kecil [41]. Penelitian yang menguji aktivitas antibakteri terhadap bakteri Gram positif (S. aureus) dan Gram negatif (E. coli) juga dilakukan oleh Foronda and Cajucom (2023) dengan sampel ekstrak etanol daging dan kulit buah naga putih.…”

Pitahaya (Hylocereus ocamponis)-Peel and -Flesh Flour Obtained from Fruit Co-Products—Assessment of Chemical, Techno-Functional and In Vitro Antioxidant Properties

“…From a commercial point of view, three varieties are widely distributed around the world. These varieties are Hylocereus megalanthus, with yellow skin and white pulp; Hylocereus undatus, with red skin and white pulp; and Hylocereus polyrhizus, with red peel and red pulp [4]. A different type of pitahaya, known as Hylocereus ocamponis, primarily inhabits the central region of Mexico, across from Nayarit to Guatemala, and it is not as commonly found in commercial markets globally [5].…”