Comparative Study of Phenolic Profiles, Antioxidant and Antiproliferative Activities in Different Vegetative Parts of Ramie (Boehmeria nivea L.)

An Integrated Study of Ramie (Boehmeria nivea), and Its Wild, Cultivated, and Feral Forms

Feralization, the re-establishment of wild populations from domesticated ancestors, can involve multiple parallel character reversions and potentially also rampant gene flow with cultivated and/or naturally wild material. It hence poses great challenges for infraspecific classification, which may impede crop development, but studies on these issues are rare. Ramie (Boehmeria nivea; Urticaceae) is an important fiber crop worldwide. It has been traditionally divided into 2-4 varieties, but these are controversial. Here, 78 wild and feral individuals were sampled from 12 Chinese provinces, plus 11 cultivated individuals from farmland. We employed an integrative taxonomy approach combining multiple lines of evidence from morphology, phylogenomics, and ecology to investigate the intraspecific subdivision of B. nivea. A chi-square test of qualitative morphological characters significantly distinguished three varieties within B. nivea: var. nivea, var. tenacissima, and the recently described var. strigosa, comprising mainly cultivated, mainly feralized, and only naturally wild material, respectively. The PCoA and random forest analyses indicated differences between var. strigosa and the other two varieties. However, quantitative characters could not distinguish the three varieties. None of the three varieties was monophyletic based on the phylogeny of plastome data, whereas var. strigosa was weakly supported as monophyletic based on nuclear ribosomal DNA (18S-ITS1-5.8S-ITS2-26S). Ecological niche modeling showed overlap between the potential distribution areas of var. nivea and var. tenacissima, but neither overlapped with var. strigosa. These analyses collectively demonstrate the distinctiveness of var. strigosa, but mostly did not fully separate var. nivea from var. tenacissima. Hence, var. strigosa is a biologically meaningful variety, but var. tenacissima should be synonymized within var. nivea. These results should aid the breeding and improvement of new varieties of ramie and highlight the value of integrative taxonomic methods in examining infraspecific subdivisions within species that include cultivated and feralized material.

Physicochemical Properties and Contents of Amino Acids, Fatty Acids, and Phytanic Acid in Goat Meat Produced by Grazing System in an Abandoned Rice Field

This study evaluated carcass weight and physicochemical properties of loin and leg meat parts of Saanen castrated goats (n = 4) reared by grazing for 5 months in an abandoned rice field with concentrate supplements, comparing with meat of goats (n = 4) reared by confined feeding with grass silage and concentrate. Carcass and meat part weights of goats in the grazing group were lower (p < 0.01) than confined group. Shear force and cooking loss of meat showed no differences between the feeding groups. For meat color, L* value of loin meat tended to be lower (p < 0.15) for the grazing group compared with the confined group. Moisture content tended to be higher, but fat content tended to be lower (p < 0.15) in loin meat for the grazing group. Carnosine and alanine contents in loin meat were higher (p < 0.05) for the grazing group. Polyunsaturated fatty acid composition in meat was higher (p < 0.05), whereas monounsaturated fatty acid composition was lower (p < 0.05) for the grazing group. Phytanic acid content in both meat parts showed higher value (p < 0.05) for the grazing group. These results indicate that goat meat produced by grazing system in an abandoned rice field contains beneficial compounds for human health.

Optimized extraction and characterization of ramie leaf polysaccharides using deep eutectic solvent and microwave: Antioxidant, metal chelation, and UV protection properties

Ramie leaf polysaccharides (RLP) were extracted using deep eutectic solvent (DES) and microwave. The extraction conditions, i.e., buffer-to-substrate (B:S) ratio (10:1-30:1 w/v), microwave power (90-270 W) and extraction duration (2-4 min) were optimized using response surface methodology. Based on the optimized model, 21.1 mL/g B:S ratio, 263 W microwave power and 2.8 min extraction time had successfully produced RLP with 16.67 ± 1.10 % (w/w) yield and 80.84 ± 1.16 % 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. The 23.4 ± 0.389 kDa RLP was a neutral polysaccharide with low carbohydrate, protein, and phenolic contents. The low galacturonic acid content (0.89 ± 0.05 mg/g) suggested RLP contained partially pectic-polysaccharide. The major monosaccharides of RLP were rhamnose, glucose, galactose and xylose. RLP was a relatively non-linear, highly branched polysaccharide with short branches based on the monosaccharide ratio. Bioactivity screening had identified the reduction (0.66 ± 0.02 mmol Fe2+/g) and copper chelation (48.5 ± 0.4 %) activities of RLP. The polysaccharide could also absorb ultraviolet (UV) in which it gave major protection against UVB with 8.7 ± 0.3 sun protection factor. These biological activities were related to specific functional groups, monosaccharide units, molecular weight and/or the neutral property of RLP. The current findings provided new insights into the antioxidant, copper chelation and sun protection benefit of RLP.

Changes in polyphenolic compounds and antioxidant activity of Japanese pickled apricot with salted red perilla leaf during pickling and digestion process

Japanese pickled apricot, called "umeboshi", is a traditional food that has experientially been consumed as a folk medicine. The main variation of umeboshi is called "shiso-zuke umeboshi", meaning pickled with red perilla leaves to add a colorful appearance. This study investigated changes in phenolics and antioxidant potential of shiso-zuke umeboshi during pickling processes and simulated digestion. Results showed that the red perilla pickling (PP; 1338.12) had 13 times higher phenolics than salt pickling (SP; 101.99) in μg/g DW, and the formation of rosmarinic acid was enhanced. The simulated digestion showed a gradual increase in antioxidant content and activity from the stomach to small intestine, with TPC and TFC being rapidly released in the intestinal environment. The study concluded that shiso-zuke umeboshi provides higher health benefits due to the excellent antioxidant compounds produced through the perilla pickling process.

Ramie leaf Extract Alleviates Bone Loss in Ovariectomized Rats-The Involvement of ROS and Its Associated Signalings

Ramie leaf (Boehmeria nivea L.) has been traditionally used to treat gynecological and bone-related disorders. This study aims to evaluate the effect of Ramie leaf extracts (RLE) against osteoporosis in ovariectomized (OVX) rats. Female SD rats aged seven weeks were randomly assigned into five OVX and a sham-operated (sham) group. OVX subgroups include OVX, vehicle-treated OVX group; E2, OVX with 100 μg/kg 17β-estradiol; and RLE 0.25, 0.5, and 1, OVX rats treated with 0.25, 0.5, and 1 g/kg/day RLE, respectively. Two weeks into the bilateral ovariectomy, all the rats were orally administered with or without RLE daily for 12 weeks. OVX rats administered with RLE showed higher bone density, relatively low tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts, and lower reactive oxygen species (ROS) within bone tissues compared to vehicle-treated OVX rats. Furthermore, supplementation of RLE improved bone mineral density (BMD) and bone microstructure in the total femur. RLE prevented RANKL-induced osteoclast differentiation and expression of osteoclastogenesis-related genes such as Cal-R, MMP-9, cathepsin K, and TRAP in RANKL-induced RAW264.7 cells. Moreover, RLE administration lowered the intracellular ROS levels by reducing NADPH oxidase 1 (NOX-1) and 4-hydroxynonenal (4HNE). These results suggest that RLE alleviates bone mass loss in the OVX rats by inhibiting osteoclastogenesis, where reduced ROS and its associated signalings were involved.

A Concise Profile of Gallic Acid-From Its Natural Sources through Biological Properties and Chemical Methods of Determination

Nature is a valuable source of anti-oxidants that have a health-promoting effect by inhibiting various undesirable changes leading to cell degradation and, consequently, potential disease ailments. One of them is gallic acid which has been used as a healing agent since ancient times. Currently, due to various beneficial properties, this compound is considered to be one of the main phenolic acids of great importance in numerous industries. It is commonly used as a substance protecting against the harmful effects of UV radiation, an astringent in cosmetic preparations, and a preservative in food products. Therefore, gallic acid is now deemed essential for both human health and industry. Increasingly better methods of its isolation and analysis are being developed, and new solutions are being sought to increase its production. This review, presenting a concise characterization of gallic acid, updates the knowledge about its various biological activities and methods used for its isolation and determination, including chromatographic and non-chromatographic methods.

Beneficial role of Boehmeria nivea in health and phytochemical constituents

The leaf and stem extracts of Boehmeria nivea (BN) collected from three different regions in Korea were screened for their antioxidant, neuroprotective, estrogenic, insulin secretion, and α-glucosidase inhibitory activity. We also examined whether BN extracts regulate cancer cell growth, inflammatory-related gene expression, and lipid accumulation in cellular system. Leaf extracts possessed greater antioxidant, anti-proliferative in cancer cells, neuroprotective, estrogenic activity, and inhibitory effect on pro-inflammatory gene expression than stem extracts. Leaf and stem extracts inhibited lipid accumulation in three T3-L1 adipocytes but did not affect glucose-stimulated insulin secretion in INS-1 cells. We isolated and identified the phytochemical constituents in the n-butanol and ethyl acetate fractions of BN leaves by combining silica gel column chromatography with mass spectrometry and ¹ H- and ¹³ C-NMR analysis. The active compounds (caffeic acid, isoquercitrin, p-coumaric acid, and rutin) exhibited ABTS and DPPH radical scavenging activity, which may contribute to the biological activities of BN leaf extract. An analytical method was developed to quantify marker compounds for the discrimination of BN collected from different regions. Our results support the use of this analysis method for accurate identification and quantification of marker compounds in BN for the development of functional foods. PRACTICAL APPLICATIONS: Boehmeria nivea (BN) has been used as a raw material for the textile industry or traditional herbal medicine. The current study established the biological activities and active components of BN. Our results showed that BN leaf and stem extracts exhibit antioxidant, neuroprotective, and estrogenic activity. BN leaf extract also inhibited cancer cell growth, inflammatory mediators and cytokines production, and lipid accumulation in vitro. Moreover, the bioactive compounds, such as caffeic acid, isoquercitrin, p-coumaric acid, and rutin, exert ABTS and DPPH radical scavenging activities. Therefore, BN could potentially be a promising source of bioactive phytochemicals for the development of functional foods or drugs.

Antimicrobial Properties of Plant Fibers

Healthcare-associated infections (HAI), or nosocomial infections, are a global health and economic problem in developed and developing countries, particularly for immunocompromised patients in their intensive care units (ICUs) and surgical site hospital areas. Recurrent pathogens in HAIs prevail over antibiotic-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. For this reason, natural antibacterial mechanisms are a viable alternative for HAI treatment. Natural fibers can inhibit bacterial growth, which can be considered a great advantage in these applications. Moreover, these fibers have been reported to be biocompatible and biodegradable, essential features for biomedical materials to avoid complications due to infections and significant immune responses. Consequently, tissue engineering, medical textiles, orthopedics, and dental implants, as well as cosmetics, are fields currently expanding the use of plant fibers. In this review, we will discuss the source of natural fibers with antimicrobial properties, antimicrobial mechanisms, and their biomedical applications.

Effect of Ramie on the Production Performance of Laying Hens, and the Quality, Nutrient Composition, Antioxidation of the Eggs

Ramie (Boehmeria nivea), which is rich in protein, fatty acid, vitamins and minerals, has become a potential alternative feed resource for poultry, and has attracted more and more attentions in nutrition research. The objective of this study is to evaluate the effect of dietary ramie at different concentrations on the production performance of the hens, and the quality, nutrient composition, and antioxidation of the eggs. A total of 432 34-week-old Lohmann commercial laying hens were divided into four groups, that were fed with corn-soybean meal-based control diet, control mixed with ramie at concentrations of 3, 6, or 9% separately for 8 weeks. Results showed that dietary ramie did not affect production performance. And egg yolk color gradually deepened as the inclusion levels of ramie increased. Ramie at tested concentration could significantly reduce the content of malondialdehyde (MDA) (p = 0.002) and 3% ramie supplementation significantly increased total antioxidative capacity (T-AOC) concentrations in egg yolk compared to the control group (p = 0.033). In addition, dietary supplementation with 6% ramie significantly reduced total cholesterol (T-CHO) content (p < 0.05) compared with controls. For egg nutrient composition, compared with the control group, the addition of 6% ramie significantly increased (p < 0.05) total omega-3 polyunsaturated fatty acids (n-3PUFA) and phenylalanine (Phe) in yolk. In conclusion, dietary inclusion of 6% ramie was most effective in improving the color, antioxidative capability, and reducing T-CHO contents of the egg yolks without any negative impacts on the production performance of the hens.

Effect of Dietary Ramie Powder (Boehmeria nivea) at Various Levels on Growth Performance, Carcass and Meat Qualities, Biochemical Indices, and Antioxidative Capacity of Linwu Ducks

Current experiment was designed to check the effect of dietary supplementation of ramie powder on the growth performance, carcass and meat qualities and antioxidative capacity of Linwu ducks. A total of 312 ducks at 21-day-age were equally divided into 4 groups, fed with control diet, control diet supplemented of 3, 6, or 12% ramie powder, respectively. The results showed that dietary supplementation of 6 and 12% ramie powder increased the final weight and daily body weight gain (P < 0.05), and dietary supplementation of 6% ramie improved the cooking loss of the leg meat 45-mins-postmortem compared with the control group (P < 0.05). Moreover, dietary supplementation of 6% ramie powder promoted the antioxidative capacity of the ducks by increasing the serum activities of superoxide dismutase and glutathione (P < 0.05), as well as the mRNA expressions of glutathione peroxidase 1 in the breast meat and superoxide dismutase 1 in the leg meat (P < 0.05). This experiment demonstrated that dietary supplementation of ramie powder showed beneficial efficacy on the growth performance of Linwu ducks. It corroborated the potential of dietary ramie being used as poultry feed ingredient and suggested that 6% was the proper supplementation rate of ramie powder in Linwu ducks' feed.

Effects of Dietary Ramie Powder at Various Levels on the Production Performance, Serum Biochemical Indices, Antioxidative Capacity, and Intestinal Development of Laying Hens

The purpose of this study was to investigate the effects of ramie (0, 3, 6, and 9%) included in diets on production performance, antioxidative capacity, serum biochemical indices, and intestinal development of laying hens. A total of 432 Lohmann commercial laying hens were randomly allotted to one of four dietary treatments and fed for 6 weeks. The results showed that the inclusion of ramie had no negative effects on laying performance, and increased (quadratic, P < 0.05) the laying rate with the highest value in the 6% ramie group. However, ramie content in the diet up to 9% reduced the apparent metabolic energy, dry matter, and organic matter apparent digestibility of laying hens compared with those in the 3% ramie group. The content of high-density lipoprotein (HDL-C) in serum was increased (P < 0.05), but the activity of aspartate aminotransferase (AST) was decreased (P < 0.05) by dietary ramie supplementation. As the dietary ramie level increased, the activity of serum glutathione peroxidase (GSH-Px) was increased quadratically (P < 0.05). Compared with control, 3% ramie group significantly increased (P < 0.01) liver total superoxide dismutase (SOD) activity. Meanwhile, the addition of 3∼6% ramie powder increased (P < 0.05) villus height of jejunum and villus height/crypt depth (V/C) of ileum, which reflected the intestinal promotional effect of ramie powder. In conclusion, ramie in a diet of less than 9% might protect the liver and improve the antioxidative capacity with no detrimental impacts on the laying hens. Moreover, it could promote the intestinal mucosal structure and have a positive impact on the intestine health of the laying hens.

Impact of sanitizer solutions on microbial reduction and quality of fresh-cut pennywort (Centella asiatica) leaves

Fresh pennywort (Centella asiatica) is usually eaten raw as 'ulam' or salad-like lettuce. Unfortunately, the fresh pennywort has the potential to cause foodborne outbreaks due to pathogens present on the surface and between the leaves, as washing the pennywort using tap water alone cannot guarantee that the pathogens are eliminated. Thus, the efficacies of several sanitizing solutions, i.e., sodium chloride, sodium hypochlorite, acetic acid, acidic electrolyzed water (acidic EW), alkaline electrolyzed water (alkaline EW), and a combination of acidic EW and alkaline EW (acidic-alkaline EW), were evaluated for their potential applications as washing solutions for pennywort. Washing using acidic EW alone or in combination with alkaline EW (two-step washing) reduced the microbial count. In sensory evaluation, all sanitizer solutions were accepted by the panellists with a score greater than 5, except those washing with acetic acid. Overall, the use of acidic EW, either alone or in combination with alkaline EW, was the best treatment to decontaminate microbes while maintaining the physicochemical and sensory properties of pennywort leaves.

Ethnobotanical Survey on Bitter Tea in Taiwan

Ethnopharmacological evidence: In Taiwan, herbal tea is considered a traditional medicine and has been consumed for hundreds of years. In contrast to regular tea, herbal teas are prepared using plants other than the regular tea plant, Camellia sinensis (L.) Kuntze. Bitter tea (kǔ-chá), a series of herbal teas prepared in response to common diseases in Taiwan, is often made from local Taiwanese plants. However, the raw materials and formulations have been kept secret and verbally passed down by store owners across generations without a fixed recipe, and the constituent plant materials have not been disclosed.

Aim of the study: The aim was to determine the herbal composition of bitter tea sold in Taiwan, which can facilitate further studies on pharmacological applications and conserve cultural resources.

Materials and methods: Interviews were conducted through a semi-structured questionnaire. The surveyed respondents were traditional sellers of traditional herbal tea. The relevant literature was collated for a systematic analysis of the composition, characteristics, and traditional and modern applications of the plant materials used in bitter tea. We also conducted an association analysis of the composition of Taiwanese bitter tea with green herb tea (qing-cao-cha tea), another commonly consumed herbal tea in Taiwan, as well as herbal teas in neighboring areas outside Taiwan.

Results: After visiting a total of 59 stores, we identified 32 bitter tea formulations and 73 plant materials. Asteraceae was the most commonly used family, and most stores used whole plants. According to a network analysis of nine plant materials used in high frequency as drug pairs, Tithonia diversifolia and Ajuga nipponensis were found to be the core plant materials used in Taiwanese bitter tea.

Conclusion: Plant materials used in Taiwanese bitter tea were distinct, with multiple therapeutic functions. Further research is required to clarify their efficacy and mechanisms.

Transcriptome and metabolome analysis reveals anthocyanin biosynthesis pathway associated with ramie (Boehmeria nivea (L.) Gaud.) leaf color formation

Background

The bast fiber crop ramie can be used as high-quality forage resources, especially in tropical or subtropical region where there is lack of high-quality protein feed. Hongxuan No.1 (HX_1) is a unique ramie variety with a light reddish brown leaf color, which is obviously different from elite cultivar, Zhongzhu No.1 (ZZ_1, green leaf). While, the regulatory mechanism of color difference or secondary metaboliates synthesis between these two varieties have not been studied.

Results

In this study, phenotypic, transcriptomic and metabolomic analysis of HX_1 and ZZ_1 were conducted to elucidate the mechanism of leaf color formation. Chromaticity value and pigment content measuring showed that anthocyanin was the main metabolites imparting the different leaf color phenotype between the two varieties. Based on LC/MS, at least 14 anthocyanins were identified in leaves of HX_1 and ZZ_1, and the HX_1 showed the higher relative content of malvidin-, pelargonidin-,and cyanidin-based anthocyanins. Transcriptome and metabolome co-analysis revealed that the up-regulated expression of flavonoids synthesis gene was positively correlated with total anthocyanins accumulation in ramie leaf, and the differentfially expression of “blue gene” (F3’5’H) and the “red gene” (F3’H) in leaves bring out HX_1 metabolic flow more input into the cyanidin branch. Furthermore, the enrichment of glycosylated modification pathway (UGT and AT) and the expression of flavonoid 3-O-glucosyl transferase (UFGT), anthocyanidin reductase (ANR), in leaves were significantly influenced the diversity of anthocyanins between HX_1 and ZZ_1.

Conclusions

Phenotypic, transcriptomic and metabolomic analysis of HX_1 and ZZ_1 indicated that the expression levels of genes related to anthocyanin metabolism contribute to the color formation of ramie variety. Anthocyanins are important plant secandary metabilates with many physiological functions, the results of this study will deepened our understanding of ramie leaf color formation, and provided basis for molecular breeding of functional forage ramie.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-08007-0.

The Antioxidant Capacities of Natural Products 2019

The search for new natural antioxidants is a growing area of research due to the broad spectrum of their biological properties, which are associated with the prevention of chronic diseases that originate in oxidative stress [...].

Extract of Boehmeria nivea Suppresses Mast Cell-Mediated Allergic Inflammation by Inhibiting Mitogen-Activated Protein Kinase and Nuclear Factor-κB

Mast cells are effector cells that initiate allergic inflammatory immune responses by inducing inflammatory mediators. Boehmeria nivea (Linn.) Gaudich is a natural herb in the nettle family Urticaceae that possesses numerous pharmacological properties. Despite the various pharmacological benefits of Boehmeria nivea, its effects on allergic inflammation have not yet been determined. Here, we investigated the effect of the ethanol extract of Boehmeria nivea (BNE) on degranulation rat basophilic leukemia (RBL)-2H3 mast cells stimulated with anti-dinitrophenyl (anti-DNP) and bovine serum albumin (BSA) during immunoglobulin E (IgE)-mediated allergic immune response. The results showed inhibition of the release of β-hexosaminidase and histamine from the cells. BNE suppressed pro-inflammatory cytokines (Tumor necrosis factor (TNF)-α, Interleukin (IL)-1β, and IL-6) and reduced T helper (Th)2 cytokine IL-4 expression and/or secretion correlated with the downregulation of p38, extracellular signal-regulated kinases (ERK) mitogen-activated protein kinase (MAPK), and nuclear factor-κB (NF-κB) signaling pathways in treated RBL-2H3 mast cells. In passive cutaneous anaphylaxis, treatment with BNE during IgE-mediated local allergic reaction triggered a reduction in mouse ear pigmentation and thickness. Taken together, these results indicated that BNE suppressed mast cell-mediated inflammation, suggesting that BNE might be a candidate for the treatment of various allergic disorders.

Laxative and antioxidant effects of ramie (Boehmeria nivea L.) leaf extract in experimental constipated rats

Ramie leaf (Boehmeria nivea L.) is rich in cellulose, polyphenol compounds, vitamin C, and minerals. The leaves of this plant, which are used for medicinal purposes, have long been reported to have anti-inflammatory, antioxidant, anticolitis, and antidiabetic effects. We investigated the protective effects of ramie leaf ethanol extract (RLE) against loperamide-induced constipation and oxidative stress in rats. Male Sprague-Dawley rats were administered 200 or 400 mg/kg body weight of RLE (RLEL and RLEH groups) by gavage, while normal (NOR) and control (CON) rats received saline. Loperamide (4.0 mg/kg, twice per day) was injected subcutaneously to induce constipation in RLEL, RLEH, and CON groups. Total fecal number, wet weight, and water content decreased, while the total number of loperamide-induced fecal pellets in the distal colon increased with administration of RLE in a dose-dependent manner. Gastrointestinal transit time was more greatly reduced in RLE-treated groups than in the CON group. Serum total cholesterol (TC) level, as well as alanine aminotransferase (ALT) and alkaline phosphatase (ALP) activity, was significantly lower in both RLEL and RLEH groups compared with the CON group. Intestinal mucosa malondialdehyde (MDA) and hydrogen peroxide (H2O2) production decreased significantly in a dose-dependent manner in the RLE-treated groups. Loperamide decreased the antioxidant enzyme activity, including that of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), while RLE administration increased the antioxidant activity. These results suggest that RLE exerts potent laxative and antioxidant effects in model rats with loperamide-induced constipation.

Comparative Assessment of Phenolic Profiles, Cellular Antioxidant and Antiproliferative Activities in Ten Varieties of Sweet Potato (Ipomoea Batatas) Storage Roots

Sweet potato is the sixth most important crop widely cultivated around the world with abundant varieties. Different varieties gain different phenolic profiles which has drawn researchers' attention for its unique health benefits. Our study evaluated the phenolic profiles, total and cellular antioxidant activities, antiproliferative activities, and cytotoxicity in 10 cultivated varieties of sweet potato in different colours. Among fourteen metabolites detected in our study, hyperoside, ferulic acid and caffeic acid were considered as prominent in SPSRs. According to the principle component analysis, phytochemical composition of HX22, YS15 and YS7 was quite similar. The results also evidenced that purple-fleshed varieties, such as YS43, YZ7 and YY153, have higher total phenolics content and corresponding stronger total antioxidant capacities as well as cellular antiproliferative activities against human liver cancer HepG2 cells than other varieties. The extremely significant correlation between phenolics and total antioxidant activity was also revealed by Pearson correlation analysis (p < 0.05). However, no significant relevance was found between intracellular antioxidant activity and total phenolic content or flesh colour of sweet potatoes.