ASSESSMENT OF THE ANTIOXIDANT, ANTIDIABETIC AND ANTIOBESITY EFFECT POTENTIALS OF PARONYCHIA ARGENTEA LAM.

Eriobotrya plants are known to have significant amounts of phenolics and flavonoids, and exhibit a strong antioxidant activity. Experiments were conducted to examine variation in the contents of total phenolics and flavonoids, and antioxidant activities in the leaves of 11 Eriobotrya species (Tibet loquat, Daduhe loquat, Hengchun loquat, Taiwan loquat, Oak leaf loquat, Bengal loquat, Fragrant loquat, Guangxi loquat, Obovate loquat, Big flower loquat, and common loquat, the last species include two materials, one is a cultivar 'Zaozhong 6', another is a wild tree). In these species, 'Zaozhong 6' loquat is a cultivar. The leaf extracts of 'Tibet', 'Obovate', 'Taiwan', 'Bengal' and 'Hengchun' loquats exhibited significantly higher contents of total flavonoids and total phenolics, compared with those of other species. Of these 11 species, the highest contents of total phenolics and total flavonoids were observed in 'Tibet' and 'Obovatae' loquats, respectively. The significantly stronger antioxidant abilities assessed by the DPPH radical scavenging activity and reducing power were obtained in the leaf extracts of 'Taiwan', 'Tibet', 'Bengal', 'Oak leaf', 'Hengchun' and 'Obovate' loquats, compared with the other species. In addition, significant correlations were found between the contents of total phenolics or flavonoids and DPPH radical scavenging activity/reducing power. This work indicates that the leaf extracts of the wild Eriobotrya species, 'Tibet', 'Obovatae', 'Taiwan', 'Bengal', 'Oak leaf' and 'Hengchun' loquats, exhibited significantly higher levels of total phenolics and flavonoids, and significantly stronger antioxidant activities, compared with the cultivated species, 'Zaozhong 6' loquat, which suggests that these wild species have a better utilization value.

본 연구는 유근피를 항산화 소재로 사용하기 위한 기초 자료를 제공하고자 에탄올의 농도(0, 40, 80% 에탄올) 및 추출시간(1, 2, 3시간)이 다른 조건에서 추출하였으며, 이들 추출물의 총 폴리페놀 및 플라보노이드 함량을 측정하였다. 또한 다양한 추출물의 DPPH 라디칼 소거능, ABTS 라디칼 소거능, 환원력, ORAC value 등의 항산화 활성을 측정하였으며, 총 폴리페놀 및 플라보노이드 함량과 항산화 활성과의 연관성을 분석하였다. 그 결과 유근피 추출물은 80% 에탄올로 3시간 추출하였을 때 가장 높은 총 폴리페놀 및 플라보노이드 함량과 항산화 활성을 보였다. 또한 DPPH 및 ABTS 라디칼 소거능, 환원력은 에탄올 함량에 따른 활성 차이는 보였으나 추출시간에 따른 항산화 활성 차이는 보이지 않았다. 하지만 ORAC는 유근피 추출물의 추출시간이 증가함에 따라 함께 증가하였다. 이상의 결과로 볼 때 유근피 추출물은 80% 에탄올을 이용하여 70°C에서 3시간 추출을 할 때 항산화 활성을 갖는 phenolic 및 flavonoid 계열의 유효성분이 가장 많이 추출되었다. 또한 유근피 80% 에탄올 3시간 추출물은 피부 섬유아세포와 3T3-L1 지방세포에서 세포독성을 나타내지 않았고 피부 섬유아세포에서 산화적 스트레스에 대한 세포 보호 효과를 가졌으며, 3T3-L1 지방세포에서 활성산소종 생성량을 감소하였다. 따라서 높은 항산화력을 가진 유근피 추출물은 천연 항산화제로 충분히 사용 가능할 것으로 사료된다.

Objective Elevated concentrations of total phenolic content (TPC) and total flavonoid content (TFC) in extracts from wild Psidium guajava L. leaves are associated with their antioxidant and α-glucosidase inhibitory activities. This study aimed to determine the optimal ultrasound-assisted extraction conditions to maximize TPC, TFC yield, as well as antioxidant and α-glucosidase inhibitory potential. Methods The central composite design (CCD) of Response Surface Methodology (RSM) was employed for empirical model development with three levels of factors, including ethanol concentration (33.18 to 66.82% in distilled water), extraction time (1.59 to 18.41 min) and solvent-to-solid ratio (5.79 to 14.20 mL/g). Results The results indicated that under optimal conditions, the total phenolic content (TPC) and total flavonoid content (TFC) values were 152.954 mg GAE/g DW and 113.871 mg QE/g DW, respectively. These conditions included an ethanol concentration of 51.94%, an extraction time of 9.56 min, and a solvent-to-solid ratio (v/w) of 10.84 mL/g. Furthermore, the maximum values for DPPH and ABTS radical scavenging activities were 124.990 mg TE/g DW and 194.730 mg TE/g DW, respectively and the lowest IC50 for α-glucosidase inhibitory activity recorded at 11.946 µg/mL. The validated models exhibited strong consistency between the predicted and experimental values, with variations of less than 5% under optimal conditions. Additionally, Principal Component Analysis (PCA) also confirmed the appropriate model to predict the extraction yield of total polyphenol and flavonoid content, as well as their biological activities, including DPPH and ABTS radical scavenging and alpha-glucosidase inhibitory activities. Conclusions The enhancement of antioxidant and antidiabetic extraction processes in both the pharmaceutical and food industries through the use of ultrasound-assisted extraction from Wild Guava leaves can increase production to meet high demand. This efficiency is particularly noteworthy, as it demonstrates the advantages of using ultrasound in the extraction process.

Solanum anguivi Lam. is an ethnomedicinal plant. Local traditional practitioners believe that it reduces the risk of diabetes and atherosclerosis diseases. The present study was intended to conduct qualitative phytochemical analysis, determine the total flavonoid and phenolic contents, estimate the antioxidant capacity and antibacterial activities of the extracts of the fruits of this plant. The antioxidant activity was determined by analyzing the radical scavenging activity (RSA) using 2,2-diphenyl-1-picryhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) assays. The antibacterial activities were determined by the agar well diffusion method. Qualitative phytochemical screening of the crude extracts obtained from the fruits of the plant indicated the presence of alkaloids, flavonoids, phenols, glycosides, steroids, terpenoids, saponins and tannins. The highest total phenolic and total flavonoid content were obtained in the ethanol extract of the fruits, followed by dichloromethane and n-hexane extract. The total phenolic content (in gallic acid equivalents, GAE) ranged from 113.3 to 202.72 mg GAE/g. The total flavonoid content (in catechin equivalent, CE) varied from 61.72 to 142.64 mg (CE)/g. All fruit extracts of S. anguivi exhibited antioxidant activity as revealed by DPPH and FRAP assays. The DPPH RSA (% inhibition) of the fruit extract varied from 35.11 to 80.13. The total phenolic and Flavonoid contents showed alinear correlation with RSA. Furthermore, all fruit extracts showed antibacterial activity against gram-positive and gram-negative bacteria varying from 12.5 to 16.75 mm. The result showed that the extracts of the plant exerted stronger bactericidal effect on gram-positive bacteria than on gram-negative bacteria. Supplemental data for this article is available online at https://doi.org/10.1080/13102818.2021.1993087 .

This study investigated the physicochemical properties (total soluble solid, salinity, pH, Hunter color value, moisture content, and viscosity), total dietary fiber (TDF) content, free sugar content, and antioxidant activities (total flavonoid content, total phenolic content, and DPPH and ABTS radical scavenging activities) of 11 types of commercial tteokbokki sauce products in Korea. The pH values of the tteokbokki sauce products were 4.62-5.83, total soluble solids were 34.60-59.40 °Brix, and salinities were 2.89-5.77%. The lightness (L), redness (a), and yellowness (b) of the Hunter color value were 23.94–43.08, 4.32–22.49, and 1.67–19.88, respectively. The moisture contents in the tteokbokki sauce products were in the range of 27.73-53.20% and the viscosity values were 373.57–7,246.33 cP. The TDF contents determined by enzymatic-gravimetric method were in the range of 0.64–4.47 g/100 g, and the free sugar contents of the tteokbokki sauce products were 13.45-32.87 g/100 g. The eleven types of tteokbokki sauce products all contained fructose, glucose, and sucrose. The total flavonoid and phenolic contents of the tteokbokki sauce products were 0.12-0.36 mg RE/g and 1.14-1.82 mg GAE/g, respectively. The DPPH and ABTS radical scavenging activities of the tteokbokki sauce products were 32.98-87.41% and 18.45-74.72%, respectively. Pearson correlation analysis revealed that the total phenolic and flavonoid content, as well as the DPPH and ABTS radical scavenging activities were positively correlated (r=0.651-0.918) with the antioxidant activities. These results provide basic data for commercial tteokbokki sauce in Korea.

Aims: This study aimed to investigate the total phenolic and flavonoid content and DPPH free-radical scavenging activity of Vernonia amygdalina planted in Mekong Delta. The optimized conditions for maceration of pandan leaves included drying method, ratio of pandan leaf powder-to-solvent, and extraction time.
 Methodology: The fresh pandan leaves were divided into two equal portions, subjected to different drying methods: shade and oven drying. The dried leaf powder was macerated in ethanol at room temperature. The maceration was conducted with 3 different ratios of pandan leaf powder-to-solvent (w/v) (1:10, 1:15 and 1:20), and the extraction time was 1, 2 and 3 days. The total flavonoid content was determined using aluminum chloride method whereas the total phenolic content was assessed using Folin-Ciocalteu assay. Meanwhile, the antioxidant activity of the plant extracts was quantitatively evaluated using DPPH test.
 Results: The results indicated that the best conditions for maceration of pandan leaves were 1:10 shade-dried leaf powder-to-solvent ratio in 1-day extraction time. Accordingly, the total flavonoid and phenolic content was found to be the highest value of 130.02 ± 2.24 mg QE/g of dried extract and 100.67 ± 1.76 mg GAE/g of dried extract (p < 0.05), respectively. The lowest IC50 of DPPH free-radical scavenging activity of pandan leaf extract was found to be 0.90 ± 0.02 mg/mL (p < 0.05). In addition, the Pearson’s correlation coefficient between IC50 of DPPH free-radical scavenge activity and total flavonoid content was R2 = 0.74 compared to that of phenolic content with the value of R2 = 0.69, indicating that the IC50 of DPPH free-radical scavenge capacity of pandan leaves was influenced chiefly by flavonoid compounds.
 Conclusion: There was a significant difference in phenolic and flavonoid content and DPPH free-radical scavenging activity between shade-dried and oven-dried pandan leaf extracts.

本試驗以綠豆抗豆象品系VC6089A、其近同源但不抗豆象品系VC1973A及日正綠豆 (日正食品工業股份有限公司，南北坊綠豆) 為材料，探討於黑暗中栽培高植化素含量綠豆芽之最適環境條件。綠豆種子於20˚C、26˚C與32˚C浸水0、4、8及12小時，其乾重隨浸種時間延長而降低。以四種密度栽培綠豆芽，收穫指數 (harvest index) 以7 g·cm-2種子最佳，其下胚軸較長、總類黃酮 (total flavonoids) 含量較高；密度試驗中，綠豆芽總酚類含量與收穫指數之間 (r=0.74***) 、總酚類 (total phenolics) 含量及總類黃酮含量之間 (r=0.77***) 皆呈正相關。以壓重0、100、200、300、400 g·51.84 cm-2栽培綠豆芽，VC1973A及日正綠豆於400 g·51.84 cm-2處理下，其豆芽下胚軸較粗短，根長亦較短；壓重試驗中，綠豆芽總類黃酮含量與DPPH自由基清除能力[α,α-diphenyl-β-picrylhydrazyl radical scavenging activity]間，以及總類黃酮含量與FRAP鐵離子氧化還原能力 (ferric reducing antioxidant power, FRAP ) 間之相關係數r分別為0.82***與0.64***。繼以16 h/8 h為一週期，於26˚C/20˚C、26˚C/23˚C、26˚C/26˚C、29˚C/20˚C、29˚C/23˚C及29˚C/26˚C栽培綠豆芽，VC6089A在29˚C/23˚C 及26˚C/26˚C栽培之鮮重較佳，VC1973A與日正綠豆則分別於29˚C/23˚C與26˚C/26˚C之鮮重較佳；綠豆芽之可溶性固形物及可溶性蛋白質含量顯著受栽培溫度組合之影響；而VC1973A綠豆芽之總類黃酮及總酚類含量皆較其他兩綠豆芽高。相較於0、10、20與50 mM氯化鈉溶液，以15 mM氯化鈉溶液栽培綠豆芽時，其產量較高、總類黃酮及總酚類含量最高，且VC1973A綠豆芽之亞鐵離子螯合能力(Fe2+ chelating ability)較高；氯化鈉試驗中，綠豆芽鮮重分別與可溶性糖含量 (r=0.83***) 、總類黃酮含量 (r=0.84***) 、總酚類含量 (r=0.85***) 及DPPH自由基清除能力 (r=0.85***) 皆呈高度正相關，而總酚類與總類黃酮含量或可作為DPPH自由基清除能力及FRAP鐵離子氧化還原能力之參考指標。以0、10、25、50、75及100 mM葡萄糖溶液栽培綠豆芽，50 mM組之抗壞血酸及總類黃酮含量較高，100 mM組含有較多的可溶性固形物及可溶性蛋白質。綜之，VC1973A綠豆芽之鮮重、外觀及植化素含量皆優於以VC6089A及日正綠豆栽培之綠豆芽。故建議於全黑暗環境下，以種子密度7 g·cm-2、壓重400 g·51.84 cm-2、15 mM氯化鈉溶液及29˚C 16 h /23˚C 8 h，栽培VC1973A綠豆芽3天，可獲得總類黃酮 (0.38 mg·g-1DW) 及總酚類含量 (11.1 mg·g-1DW) 、亞鐵離子螯合能力 (84.8 % of 50 mg DW·mL-1) 、DPPH自由基清除能力 (54.1 % of 50 mg DW·mL-1)與FRAP鐵離子氧化還原能力 (150.9 µmol FeSO4·g-1DW) 最高、且產量 (54.5 g FW·51.84 cm-2) 亦佳之綠豆芽。

Dissotis erecta is a shrubby herb belonging to the Melastomataceae family, commonly found in Nigeria. It is widely recognized for its diverse ethnomedicinal applications, including treating edema, diarrhea, stomach discomfort, and rheumatism. Alongside other plant parts, its flowers, rich in biologically active compounds, are valued for their aesthetic appeal and potential health benefits. This study assessed the antioxidant properties, total phenolic, total flavonoid, and bioactive contents of the methanolic extract of D. erecta flowers. The antioxidant properties were determined by the DPPH radical scavenging activity, ABTS radical scavenging activity, ferric reducing activity, and metal chelating assay. The extract demonstrated strong DPPH radical scavenging activity, ABTS radical scavenging activity, metal chelating ability, and reducing power, with IC50 values of 79.84 ± 0.64 µg/mL, 125.77 ± 2.64 µg/mL, 87.89 ± 0.91 µg/mL, and 71.71 ± 0.55 µg/mL, respectively. Phytocompounds such as alkaloids, sterols, and terpenoids were present in the flower extract, while phlobatanins and glycosides were absent. Total phenolic content was 57.47 ± 0.21 mg GAE/g, while total flavonoid content was 83.52 ± 0.31 mg QE/g. Gas chromatography-mass spectroscopy (GC-MS) analysis identified α-terpineol (86.53%), nerolidol (7.44%), campesterol (1.12%), and neocurdione (1.29%) as the predominant components. These findings indicate that D. erecta flowers contain a significant amount of phytocompounds with antioxidative properties that could potentially be useful in managing diseases related to oxidative stress.

Purpose: To evaluate the total phenolic and flavonoid contents of Mentha spicata (MS) leaves aqueous extracts obtained from different regions (El-Oued, Tebessa and El-Tarf) of Algeria, as well as their in vitro antioxidant and antidiabetic activities.
 Methods: Aqueous extracts were obtained from the air-dried leaves of MS by maceration followed by filtration and evaporation using a rotary evaporator. Folin-Ciocalteu and Aluminium chloride colorimetric techniques were used to determine the total phenolic and flavonoid contents, respectively. The radical DPPH, ABTS, and FRAP tests were used to determine their antioxidant activities, while the in vitro inhibition percentages of α-amylase and α-glucosidase enzymes were used to assess the anti-diabetic activity.
 Results: The El-Oued's extract exhibited the highest total phenolic content (108.94 mg GAE/g dry extract (DE)), while the highest total flavonoid content (0.039 mg QE/g DE) was found in El-Tarf's extract. The radical DPPH and FRAP scavenging activity of the El-Oued extract exhibited the highest inhibition activities (IC50 = 102.5 and 289.5 μg/mL), respectively, while the ABTS inhibition activity of the El-Tarf extract exhibited a maximum IC50 value of 111 ± 2.8 μg/mL. The MS extract of the El-Oued region had the highest α-amylase and α-glucosidase enzyme activities with IC50 values of 121.4 and 216.9 μg/mL, respectively.
 Conclusion: The leaves of Mentha spicata exhibit high phenolic and flavonoid contents, along with significant antioxidant and antidiabetic properties. This study reveals that Mentha spicata flavonoid and phenolic contents as well as other properties vary by region.

Objective: The present study was undertaken to evaluate the total phenolic and flavonoid content and the antioxidant property of two important seagrass species namely, Halophila ovalis and Halophila beccarii occurring in Chilika lagoon, Odisha, India.
 Methods: Total Phenolic Content (TPC) of the extracts of Halophila species was determined by Folin-Ciocalteu method with little modifications and the total flavonoid content (TFC) was measured by aluminum chloride colorimetric assay. The antioxidant activity of different extracts was investigated by DPPH and ABTS radical scavenging activity. IC50 values were calculated for the DPPH and ABTS methods.
 Result: The study revealed that the methanol extract of H. ovalis has greater antioxidant activity than H. beccarii. Methanol extract of both the species (H. ovalis and H. beccarii) was found to possess high phenolic content at value of 70.25 mg GAE/g of extract and 48.53 mg GAE/g of extract respectively. Similarly flavonoid contents was found highest in methanol extract for both H. ovalis (76.82 mg quercetin equivalent/ g of extract) and H. beccarii (64.28 mg quercetin equivalent/ g of extract). The antioxidant activity of different extracts of these two species were evaluated using DPPH and ABTS radical assay. The methanol extract of both H. ovalis and H. beccarii showed high radical scavenging activity with IC50 values of 37.77 μg/ml and 52.25 μg/ml for DPPH and 25.62 μg/ml and 45.45 μg/ml for ABTS respectively.
 Conclusion: The study revealed the potential of the Halophila species as natural sources of antioxidants having considerable commercial importance.

This study examined the antioxidant chemical constituents (total phenolic and total flavonoid contents) and antioxidant activities [1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging, and ferric reducing antioxidant power (FRAP)] of different solvent extracts of eighteen functional plants. The active components of the target plants were extracted using four different solvents (methanol, ethanol, chloroform, and water). Mentha piperascens leaf exhibited a higher total phenolic content (chloroform and water extracts), total flavonoid content (all solvent extracts), DPPH radical scavenging activity (methanol, ethanol, and water extracts), ABTS radical scavenging activity (water extract), and FRAP radical scavenging activity (water extract) (in all solvent extracts). Similarly, Petasites japonicas root was another excellent and competent extract with a high total flavonoid content (in all four solvent extracts), DPPH and ABTS radical scavenging activity (methanol, ethanol, and water extracts), and FRAP activity (methanol, ethanol, and water extracts) (in all solvent extracts). Rubus coreanus fruit had the highest total phenolic content (methanol, ethanol, and water extracts), DPPH and ABTS radical scavenging activate (in all solvent extracts), and FRAP in its water extract were the two most effective functional plants. Based on the abundance of antioxidant chemical constituents and the most potent antioxidant activity demonstrated in this study, extracts from M. piperascens leaf, P. japonicas root, and R. coreanus fruit appear to be promising candidates to meet the current demand for natural preservatives in food and pharmaceutical industries.

Aims: Plants need an appropriate amount of nutrients such as copper for growth and development. However, excess of copper may interrupt plant development and cause stress that led to biochemical compounds being synthesized. The influence of a high copper sulfate concentration on phenolic and flavonoid content in Phyllanthus tenellus plants was investigated.
 Place and Duration of Study: The experiment was conducted in a government compound at MARDI Serdang, Selangor, Malaysia (2° 59' 31.7292'' N 101° 41' 56.706'' E), from April 2021 to Jun 2021.
 Methodology: The experiment was conducted using a vertical column planting system under a side-netted rain shelter. The plants were subjected to 0.5 M copper sulfate sprayed after 60 days of planting and harvested 0.5, 1.5, 3, 6, 12 and 24 h after sprayed for further analysis. Total phenolic content was calculated as mg gallic acid equivalent and total flavonoid content was measured as quercetin equivalent.
 Results: Highest total phenolic and flavonoid content was detected after 0.5 hours of copper sulfate application and started to decrease towards 24 hours after sprayed. Treated samples showed a 1.18-fold increase in total phenolic content and 1.4-fold increase in total flavonoid content compared to control untreated samples after 0.5 hours of sprayed. Control samples showed stability in both total phenolic and flavonoid content throughout the harvesting periods. Phenolic is the major secondary metabolites in Phyllanthus tenellus plants.
 Conclusion: Data revealed that the application of 0.5 M copper sulfate is able to enhance total phenolic and flavonoid content in Phyllanthus tenellus plants. The study suggested that the optimum harvesting time is 0.5 hours after copper sulfate application.

Medicinal plants are good sources and rich of substances which having nutraceutical and health benefits. Valeriana officinalis L. (Valerianaceae) is a known medicinal plant used in traditional medicine worldwide. The aim of present study was to evaluate the efficiencies of three methods for evaluated for antioxidant from Valeriana officinalis. Besides, the impact of extraction methods on total phenollic and flavonoids contents and antioxidant activities of Valeriana root was investigated. The dried-root was extracted by three different methods including maceration, ultrasonic assisted, and Soxhlet assisted extraction. Antioxidant capacity was assessed using four different methods: DPPH and nitric oxide (NO) free radicals scavenging, reducing power and iron chelating activity. The total phenolic and flavonoid contents were also identified. The ultrasonic extract showed highest amount of total phenolics and flavonoids contents. In DPPH radical scavenging activity, the ultrasonic assisted extract, (IC50=0.546 μg/ ml) had a higher activity from other extracts. In reducing power assay, maceration extract showed the highest activity. In DPPH radical scavenging activity, IC50 for ultrasonic extract, soxhlet assisted extraction and maceration extract were 0.546, 0.816 and 0.678 μg/ml, respectively. Here, the maceratin extract showed the highest activity, too. The results clearly indicated the extraction methods used in this study significantly affected antioxidant capacities and total phenolic and flavonoids contents. Ultrasonic assisted extraction and Soxhlet methods were found to be more efficient in extraction of antioxidant components of valeriana.

Medicinal plants are good sources and rich of substances which having nutraceutical and health benefits. Valeriana officinalis L. (Valerianaceae) is a known medicinal plant used in traditional medicine worldwide. The aim of present study was to evaluate the efficiencies of three methods for evaluated for antioxidant from Valeriana officinalis. Besides, the impact of extraction methods on total phenollic and flavonoids contents and antioxidant activities of Valeriana root was investigated. The dried-root was extracted by three different methods including maceration, ultrasonic assisted, and Soxhlet assisted extraction. Antioxidant capacity was assessed using four different methods: DPPH and nitric oxide (NO) free radicals scavenging, reducing power and iron chelating activity. The total phenolic and flavonoid contents were also identified. The ultrasonic extract showed highest amount of total phenolics and flavonoids contents. In DPPH radical scavenging activity, the ultrasonic assisted extract, (IC50=0.546 g/ml) had a higher activity from other extracts. In reducing power assay, maceration extract showed the highest activity. In DPPH radical scavenging activity, IC50 for ultrasonic extract, soxhlet assisted extraction and maceration extract were 0.546, 0.816 and 0.678 g/ml, respectively. Here, the maceratin extract showed the highest activity, too. The results clearly indicated the extraction methods used in this study significantly affected antioxidant capacities and total phenolic and flavonoids contents. Ultrasonic assisted extraction and Soxhlet methods were found to be more efficient in extraction of antioxidant components of valeriana.

Six cultivars of kiwifruits grown in Korea, including Actinidia eriantha ‘Bidan’, A. arguta ‘Chiak’, A. arguta ‘Darae No. 2’, A. chinensis ‘Haegeum’, A. chinensis ‘Haehyang’, and A. arguta × A. deliciosa ‘Mansoo’, were harvested at various maturity stages to test whether kiwifruit maturity has an influence on antioxidant capacity or total phenolic and flavonoid contents. Kiwifruit extracts were isolated using absolute methanol and then 80% (v·v-1) aqueous methanol during homogenization. ‘Bidan’, collected at the second harvest stage, contained the greatest amount of total phenolics (775.3 mg gallic acid equivalents·100 g-1 fresh weight) and had the highest antioxidant capacity [816.5, 633.2, and 2,662.7 mg vitamin C equivalents·100 g-1 fresh weight for 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) scavenging, 1,1-diphenyl-2-picrylhydrazyl scavenging, and oxygen radical absorbance capacity assays, respectively] among cultivars tested, while ‘Haehyang’, collected at the first harvest, contained the greatest amount of total flavonoids (13.1 mg catechin equivalents·100 g-1 fresh weight). Kiwifruit cultivar and genotype influenced antioxidant capacity, as well as total phenolic and flavonoid contents. No trend, however, was observed in total phenolic and flavonoid contents, and in the antioxidant capacity with respect to maturity stage. Antioxidant capacity had a higher linear correlation coefficient with total phenolic contents than with total flavonoid contents. The results above suggest that kiwifruits at various maturity stages are a valuable source of phenolics and antioxidants for industrial application and consumer health benefit.