Composition and Antioxidative and Antibacterial Activities of the Essential Oil from Farfugium japonicum.

The composition of volatile oils of the leaf and stem of Farfugium japonicum (L.) Kitamura were prepared by supercritical fluid extraction (SFE)-CO2. A total 47 and 40 compounds were identified by GC/MS analysis, respectively, and only 13 compounds coexisted. The main constituent types in the leaf oil included alcohols (34.1%), hydrocarbons (24.1%), terpenoids (16.2%), benzenes (7.5%), and fatty acids (4.9%). In the stem oil, the constituent types chiefly included benzenes (18.8%), ketones (13.9%), terpenoids (17.0%), fatty acids (8.8%), phenolics (8.7%), steroids (8.6%), hydrocarbons (8.0%), and esters (5.7%). The predominant volatile compounds in the stem were 2-(1-cyclopent-1-enyl-1-methylethyl) cyclopentanone (11.7%), 1,2,3,4,5,6,7,8-octahydro- 9,10-dimethyl-anthracene (8.4%), 5-heptylresorcinol (6.5%), and α-sitosterol (5.2%). Those in the leaf mainly included (E)-3-hexen-1-ol (13.7%) and (Z)-3-hexen-1-ol (14.0%). This demonstrated a significant difference in the composition of both oils. Further study showed that stem oils demonstrated the highest DPPH (1,1-diphenyl-2-pinylhydrazyl) and ·OH free radical scavenging capacities at IC50 values of 9.22 and 0.90 mg/mL, respectively. In addition, they demonstrated the strongest antibacterial capacity against the Gram-positive bacteria methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) at a minimum inhibitory concentration (MIC) of 0.16 mg/mL. This could be due to the SFE-CO2 extraction and the high accumulation of benzenes, terpenoids, and phenolics in the stem. In particular, the monoterpenes presented in terpenoids could play a special role in these findings.

First Report of Leaf Spot in Farfugium japonicum Caused by Alternaria alternata in China.

Farfugium japonicum (L.) Kitam (with the common name leopard plant) is known as a garden and medical herb, and belongs to the family Asteraceae. In May 2019, a leaf spot disease was observed on the upper leaf surface of F. japonicum in Changsha city, Hunan province, China. More than 98% of the F. japonicum plants were infected in a garden of Donghu district (28°13' N; 112°56' E). Leaf symptoms included small (1 to 10 mm in diameter), brown spots that were circular, tan to gray in the center and distinct brownish-yellow margins. Severely affected leaves were blighted and plants were dying. For isolation, symptomatic leaf tissue was surface sterilized, rinsed in sterile distilled water, and plated on potato dextrose agar (PDA) amended with a 50 µg/ml streptomycin sulfate followed by incubation at 25°C in darkness. By a single-spore isolation technique, pure fungal cultures were obtained and displayed gray-brown and gray-white aerial mycelia after five days of incubation. One representative isolate (HnAa-1) was selected for further studies. Conidia of HnAa-1 were olive brown, obpyriform, either branched or unbranched with a short beak, 1 to 5 transverse septa, and 0 to 3 longitudinal or oblique septa. The conidia were 10 to 35 µm long and 2 to 12 µm wide. HnAa-1 was identified as an Alternaria sp. on the basis on morphological characterization by Simmons (1). Further identification to species level was made by molecular analyses. DNA of HnAa-1 was extracted from the regions internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and partial Alt a 1 major allergen (ALT) gene. Amplification and sequencing was carried out with the method described by Woudenberg et al.(2) . BLASTn searches showed that the ITS, GAPDH and ALT sequences had the highest similarity with A. alternata strains, with 100% (548/548) identities for ITS (GQ169728), 100% (567/567) identities for GAPDH (MK903028) and 99.36% (466/469) identities for ALT (MN184998). Moreover, the ITS, GAPDH and ALT sequences had more than 99% identities with the epitype CBS 916.96 of A. alternata (ITS: AF347031; GAPDH: AY278808; ALT: AY563301). The ITS, GAPDH and ALT sequences of HnAa-1 were submitted to GenBank (Accession No. MT767170, No. MW115639 and No. MW316727). Pathogenicity tests were conducted by spraying a 10 ml conidial suspension (1.0 ×105 conidia /mL) on surfaces of leaves of three healthy plants (8-week-old). Leaves of three healthy plants were sprayed with sterile distilled water as a control treatment. All inoculated plants were maintained in growth chamber at 25°C with a 12-h photoperiod. The pathogenicity test was repeated twice. After five days inoculation, typical brown spots and necrotic lesions similar to those observed in the field, had developed on all inoculated plants but not on water-treated control plants. Alternaria alternata was re-isolated from the symptomatic tissue of inoculated plants but not from the control plants, and re-identified with morphological and molecular methods, which fulfilled Koch's postulates. This host-pathogen association has been reported in Korea (3), but it is the first report of A. alternata causing leaf spots on F. japonicum in China. Since A. alternata is a ubiquitous and very important plant pathogen causing leaf spot diseases in over 100 species plant, the occurrence of this disease is a serious threat to F.japonicum and might lead to economic losses. Therefore, appropriate prevention strategies to F.japonicum should be adopted.

Effect of strong wind on laminas and petioles of Farfugium japonicum (L.) Kitam. var. japonicum (Asteraceae).

Farfugium japonicum (L.) Kitam. var. japonicum grows mainly in the coastal areas of Japan. Meteorological recording data from natural habitats were used to investigate the factors associated with the laminas and petioles of radical leaves of F. japonicum var. japonicum to avoid or resist higher wind stress. Our morphological and mechanical results indicated that petiole length and petiole cross-sectional area had a weak correlation with wind speed and breaking strength, and the petiole second area moment of inertia did not differ significantly among populations. However, both lamina area and petiole length per petiole cross-sectional area decreased with increasing wind speed, indicating that F. japonicum var. japonicum resisted or avoided an increase in wind speed outdoors by reducing the lamina area and petiole length per petiole cross-sectional area without qualitative changes in their petioles. The results of this study indicated that densely distributed recording stations of the Automated Meteorological Data Acquisition System (AMeDAS) by the Japan Meteorological Agency can be used for environmental adaptation studies of plants in the field using nearby plant populations.

Bioactive phenolic compounds from the flowers of Farfugium japonicum (L.) Kitam. var. giganteum (Siebold et Zucc.) Kitam. (Asteraceae).

Farfugium japonicum (L.) Kitam. var. giganteum (Siebold et Zucc.) Kitam. is mainly distributed in the Kyushu and Shikoku Islands of Japan. The main aim of this study was to isolate and identify the chemical constituents of the 70% EtOH extract of the flowers of F. japonicum var. giganteum and to evaluate their tyrosinase inhibitory and free radical scavenging activities. Five phenolic compounds, namely petasiphenol (1), rosmarinic acid (2), 4,5-di-O-caffeoylquinic acid (3), 5-O-caffeoylquinic acid (4) and quercetin (5) were isolated and their structures were elucidated on the basis of NMR spectroscopic data. All these compounds were isolated for the first time from title plant. Among them, petasiphenol (1) showed potent tyrosinase inhibitory activity followed by quercetin (5) and 4,5-di-O-caffeoylquinic acid (3). All of these compounds showed potent free radical scavenging activity.

Characterization of the complete chloroplast genome of Farfugium japonicum (Asteraceae).

The complete chloroplast genome of Farfugium japonicum, which belongs to tribe Senecioneae (Asteraceae) was characterized. The size of the chloroplast genome is 151,222 bp in length with a large single copy (LSC) of 83,417 bp, a small single copy (SSC) of 18,125 bp, and a pair of inverted repeats of 24,840 bp. The chloroplast genome encodes a set of 133 genes, including 88 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Phylogenomic analysis based on chloroplast genomes of 18 related species revealed that F. japonicum is clustered with species from Ligularia and rooted with the other Senecioneae genus. The chloroplast genome of Farfugium japonicum provides an important resource for further study of molecular evolution.

First Report of Leaf Rust Caused by Puccinia caricis in Farfugium japonicum in Korea.

Farfugium japonicum is used in traditional medicine and as an edible herb in China and Korea. In July 2013, leaf spots were observed in F. japonicum seedlings at Ulleung Island, Gyeongsangbuk Province, Korea. Early symptoms on the leaf adaxial surface included roughly circular yellow spots that later developed brown, necrotic centers. The aecia were hypophyllous, cupulate, yellowish, 180~430 µm in diameter, clustered, and erumpent with a peridium with a recurved margin. The aeciospores were globoid, 14~17 × 13~16 µm, light yellow or colorless, and densely verrucose. The 28S rDNA sequence of the isolate was identical to each other and shared 99% identity with Puccinia caricis. This is the first report of rust caused by P. caricis in F. japonicum in Korea or elsewhere in the world.

Quantitative Determination of Bakkenolide D in Petasites japonicus and Farfugium japonicum by HPLC/UV

A quantitative analysis of bakkenolide D in the different parts of Petasites japonicus and Farfugium japonicum was performed by HPLC. A gradient HPLC elution system with a mobile phase consisting of water:acetonitrile solution (20:80 to 0:100 for 45 min) was followed and an INNO C₁₈ column was used for the chromatographic separation. The injection volume, flow rate, and UV detection were 10 µL, 1 mL/min, and 290 nm, respectively. Results show that both species showed the highest amount of bakkenolide D in the roots being 107.203 and 166.103 mg/g for P. japonicas and F. japonicum, respectively. Content analysis on the different parts of both plants displayed remarkably lower values which ranged from 0.403 – 4.419 and 7.252 – 32.614 mg/g for P. japonicas and F. japonicum, respectively. The results show that the roots of both plants are rich in bakkenolide D showing a promising use in the development of nutraceuticals and industrial application of the compound.

First Report of Leaf Rust Caused by Puccinia caricis in Farfugium japonicum in Korea

Farfugium japonicum is used in traditional medicine and as an edible herb in China and Korea. In July 2013, leaf spots were observed in F. japonicum seedlings at Ulleung Island, Gyeongsangbuk Province, Korea. Early symptoms on the leaf adaxial surface included roughly circular yellow spots that later developed brown, necrotic centers. The aecia were hypophyllous, cupulate, yellowish, 180~430 microm in diameter, clustered, and erumpent with a peridium with a recurved margin. The aeciospores were globoid, 14~17 x 13~16 microm, light yellow or colorless, and densely verrucose. The 28S rDNA sequence of the isolate was identical to each other and shared 99% identity with Puccinia caricis. This is the first report of rust caused by P. caricis in F. japonicum in Korea or elsewhere in the world.