Implications of the Propagation Method for the Phytochemistry of Nepeta cataria L. throughout a Growing Season.

Catnip (Nepeta cataria L.) plants produce a wide array of specialized metabolites with multiple applications for human health. The productivity of such metabolites, including nepetalactones, and natural insect repellents is influenced by the conditions under which the plants are cultivated. In this study, we assessed how field-grown catnip plants, transplanted after being propagated via either single-node stem cuttings or seeds, varied regarding their phytochemical composition throughout a growing season in two distinct environmental conditions (Pittstown and Upper Deerfield) in the state of New Jersey, United States. Iridoid terpenes were quantified in plant tissues via ultra-high-performance liquid chromatography with triple quadrupole mass spectrometry (UHPLC-QqQ-MS), and phenolic compounds (phenolic acids and flavonoids) were analyzed via UHPLC with diode-array detection (UHPLC-DAD). The highest contents of total nepetalactones in Pittstown were found at 6 weeks after transplanting (WAT) for both seedlings and cuttings (1305.4 and 1223.3 mg/100 g, respectively), while in Upper Deerfield, the highest contents for both propagules were at 11 WAT (1247.7 and 997.1 mg/100 g, respectively) for seed-propagated and stem cuttings). The highest concentration of nepetalactones was associated with floral-bud to partial-flowering stages. Because plants in Pittstown accumulated considerably more biomass than plants grown in Upper Deerfield, the difference in nepetalactone production per plant was striking, with peak productivity reaching only 598.9 mg per plant in Upper Deerfield and 1833.1 mg per plant in Pittstown. Phenolic acids accumulated in higher contents towards the end of the season in both locations, after a period of low precipitation, and flavone glycosides had similar accumulation patterns to nepetalactones. In both locations, rooted stem cuttings reached their maximum nepetalactone productivity, on average, four weeks later than seed-propagated plants, suggesting that seedlings have, overall, better agronomic performance.

Repellency of novel catnip (Nepeta cataria) cultivar extracts against Ixodes scapularis and Haemaphysalis longicornis (Acari: Ixodida: Ixodidae).

Tick bites are a major public health concern due to the vector role that many tick species have in transmitting human pathogens. Synthetic repellents such as N­diethyl-meta-toluamide (DEET) remain the standard for repellency. Still, there is a need for natural commercial alternatives with similar or better properties than DEET. We evaluated the repellency of two extracts, CR3 and CR9, derived for newly developed catnip cultivars on two tick species, Ixodes scapularis and Haemaphysalis longicornis. Dose-response in vitro assays showed that CR3 and CR9 extracts have similar repellency properties to DEET. At a 20% concentration, both CR3 and CR9 extracts exhibited a repellency of 100%. Catnip extracts maintained their repellency properties for at least 8 h. In a two-choice assay, I. scapularis, but not H. longicornis, was more sensitive to CR3 than DEET. In addition, CR3 reduces the life span of I. scapularis, suggesting that it has an acaricidal effect on ticks. In summary, CR3 and CR9 catnip extracts are promising tick repellents that should be further developed, alone or in combination with other tick repellents, and tested for their use as tick repellents for humans.

Antiviral activity of aframomum melegueta against severe acute respiratory syndrome coronaviruses type 1 and 2.

Plant-based compounds with antiviral properties against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been identified in Aframomum melegueta through computational models. The seed extract have been traditionally used to treat different illnesses. In this study, ethanolic extracts were prepared for six commercial samples of A. melegueta seeds. Antiviral activity was tested using the XTT cytotoxicity assay and cell-based SARS-CoV-1 and 2 pseudoviral models. The presence of gingerols and other non-volatile components in the seed extracts was determined using an Agilent 1290 UPLC/DAD in tandem with an Agilent 6546 QTOF-MS. Our results showed selective antiviral activity with TI values as high as 13.1. Fifteen gingerols were identified by chromatographic analysis, with 6-gingerol being the dominant component in each seed extract. A combination of 6-gingerol with techtochrysin, previously identified in computational models as a potential active ingredient against SARS-CoV-2, demonstrated additive antiviral activity with CI values between 0.8715 and 0.9426. We confirmed the antiviral activity of A. melegueta predicted through computational models and identified a different compound, 6-gingerol, as a potential active ingredient.