ACHE x BCHE x TYR

Understanding the bioactive potential of plant extracts requires detailed evaluations of their chemical composition and bioactivities. This study investigated the chemical profiles, antioxidant properties, and enzyme inhibitory activities of water and methanol extracts of Stachys chasmosericea Ayasligil & P.H.Davis obtained via ultrasound-assisted extraction. The methanol extract displayed significantly higher total phenolic and flavonoid contents compared to the water extract. Chromatographic analysis revealed verbascoside and chlorogenic acid as the dominant compounds in the methanol extract, whereas the water extract contained higher levels of polar compounds like p-coumaric acid. Antioxidant assays demonstrated the methanol extract's superior activity. Conversely, the water extract excelled in metal chelation. RACI values confirmed the methanol extract's overall antioxidant superiority (RACI = 0.65) over the water extract (RACI = -0.65). Enzyme inhibition assays revealed the methanol extract's stronger activity against AChE, BChE, α-amylase, α-glucosidase, and tyrosinase whereas the water extract showed weaker inhibition. Both extracts demonstrated potential for managing oxidative stress and enzyme-related disorders but require further in vivo validation. This study highlights S. chasmosericea, particularly its methanol extract, as a promising source of natural antioxidants and enzyme inhibitors. Future research should focus on isolating individual bioactives and exploring their mechanisms of action in biological systems.

The antioxidant and enzyme inhibition properties of the isoflavone genistein ( 1 ) and the alkaloid 11‐α‐hydroxyerysotrine ( 2 ) isolated from the leaves of Erythrina speciosa were assessed. Both compounds exhibited notable in vitro antioxidant activities; 11‐α‐hydroxyerysotrine ( 2 ) demonstrated stronger effects than genistein in DPPH, ABTS, CUPRAC, and FRAP assays. On the other hand, genistein ( 1 ) demonstrated a higher metal chelating activity than 11‐α‐hydroxyerysotrine ( 2 ). Regarding enzyme inhibition, 11‐α‐hydroxyerysotrine ( 2 ) inhibited both acetyl‐ (AchE) and butyryl‐ (BchE) cholinesterases, though to a lesser extent than the standard drug galanthamine. Both compounds inhibited tyrosinase, yet a good inhibition was observed for 11‐α‐hydroxyerysotrine ( 2 ) as compared to genistein ( 1 ). Genistein ( 1 ) showed a lower α‐amylase inhibition effect (IC 50 : 3.43 mg/mL, p  < 0.05) compared to the standard acarbose (IC 50 : 0.80 mg/mL). Regarding α‐glucosidase inhibition, genistein ( 1 ) (IC 50 : 1.02 mg/mL, p <  0.05) was more active than acarbose (IC 50 : 1.78 mg/mL). 11‐α‐Hydroxyerysotrine ( 2 ) exhibited lower α‐amylase (IC 50 : 4.09 mg/mL) and α‐glucosidase (IC 50 : 4.48 mg/mL) inhibition effects. The in vitro biological results were further supported by network pharmacology approaches on Alzheimer's disease and in silico studies performed on AChE, BChE, tyrosinase, α‐amylase, and β ‐glucosidase enzymes. The results of our study suggest 11‐α‐hydroxyerysotrine as a potential drug candidate for further investigation in managing oxidative stress‐related conditions, Alzheimer's disease, and hyperpigmentation disorders.

Organohalogen natural products play a crucial role in drug research, with halogenation generally enhancing the bioactivity of natural compounds. Chlorinated natural compounds, a major category of organohalogens, are found in both marine and terrestrial environments. Among these, terpenoids are abundant compounds with diverse structures. Guaiane-type sesquiterpene lactones, with a [5,7,5] tricyclic skeleton, are one such class. Since the first examples in 1968, 102 natural chlorinated guaiane-type sesquiterpene lactones has been isolated from Asteraceae family plants. These compounds exhibit significant structural diversity, with chlorine located at various positions, including C-1, C-2, C-3, C-4, C-5 in the cyclopentyl, and C-13, C-14, C-15, and C-18 at the C-8 substituent. Determining the structure of these compounds, especially regarding chlorine position and stereochemistry, is challenging, with some structures revised using chemical computational techniques. Although few studies have examined their bioactivity, these compounds exhibit various bioactivities, including cytotoxic, anti-inflammatory, melanogenesis and tyrosinase stimulation, antimicrobial, antiviral, neuroprotective, inhibition effects on butyrylcholinesterase and acetylcholinesterase, and hematopoietic stem cell expansion activities. This review summarizes the natural origin, structural and NMR characteristics, and bioactivities of these rare compounds, offering an overview of their current research status, future pharmaceutical potential, and highlighting existing gaps and further directions.