Table 2.
Plant-derived compounds with cognition-improving effect in diet-induced obese animal models.
| Isolated Compounds | Source(s) | Treatment Mode; Dose; Duration | Central Effects | Other Effects | Obesity Model; Strain; Species; Gender | Ref. |
|---|---|---|---|---|---|---|
| β-glucan | Oats | Oral β-glucan from oats (7 g/100 g of daily food intake) + HFD; 15 weeks and short-term for 1 week | decreased microglial activation and inflammation; promoted synaptogenesis; improved insulin signaling; inhibited Tau phosphorylation; improved synaptic plasticity | weight loss (long-term treatment); reversed gut barrier dysfunction; increased thickness of colonic mucus; increased level of tight junction proteins; ameliorated altered microbiota | HFFD (55% by energy; 5% fiber by weight); C57BL/6J mice; Male | [74] |
| Caffeine | Coffee, tea | Intraperitoneal caffeine; 20 mg/kg; once weekly; 11 weeks | reversed decrease in BDNF levels | weight loss; decreased plasma insulin levels | HFD (31.8% of energy as fat); SD rats; Male | [75] |
| Chlorogenic acid | Various plants | Oral chlorogenic acid; (150 mg/kg/day) + HFFD; 14 weeks | ameliorated hippocampal structural damage and synaptic dysfunction; decreased inflammation; improved cholinergic synapse and calcium signaling pathway | weight loss; reduced insulin resistance and lipid profile; increased gut microbiota diversity and bacteria producing SCFA; significant decrease in TG, TC, LDL, and significantly increased HDLs | HFHS (45% kcal from fat, 10% fructose in drinking water) C57BL/6J mice; Male | [76] |
| Curcumin | Turmeric (Curcuma longa) | Oral curcumin ad libitum; 1000 mg/kg diet; 12 weeks | anti-inflammatory or antioxidant actions | no weight loss effect | Ad libitum standard diet (4.1% energy as fat); C57BL/6 mice; Male | [77] |
| Formononetin | Red clover (Trifolium pratense) | Intragastric (20,40 mg/kg); 10 weeks | Decreased Tau hyperphosphorylation; reduced cytokines | weight loss | HFD (10% lard oil, 1% cholesterol, 0.2% cholate; 5% sucrose); ICR mice; Male | [78] |
| Huperzine A | Chinese club moss (Huperzia serrata) | Intragastric or oral Hup A (0.1 mg/kg/day and 0.3 mg/kg/day); 12 weeks | increased insulin and AKT activity; decreased beta-secretase expression | no weight loss effect | HFD (60% energy from fat, 20% from protein, and 20% from carbohydrates); C57 BL/6 mice; Male | [79] |
| Iso-α-acids | Hops (Humulus lupulus) | Oral iso-α-acids group; daily 0.05% (w/w) + HFD; 8 weeks | attenuated neuroinflammation and lipid peroxidation; prevented hippocampal atrophy | weight loss; decreased epididymal fat and plasma triglyceride levels | HFD (60 kcal% from fat); C57BL/6 J mice; Male | [80] |
| Isorhamnetin | Sea-buckthorn (Elaeagnaceae genus) | Oral daily isorhamnetin (0.03% w/w and 0.06% w/w) in HFFD; 14 weeks | inhibited microglial overactivation and neuroinflammation; increased activity of neurotrophic factors | weight loss; improved serum and liver lipids: TC, TG, LDL, HDL | HFHFD (45% kcal from fat, 10% kcal from fructose water); C57BL/6J; Male | [81] |
| Luteolin | Dyer’s rocket (Reseda luteola) | Oral daily; 10 mg/kg in HFD; 20 weeks | decreased neuroinflammation, oxidative stress, and neuronal insulin resistance; increased BDNF levels, synapsin U and PSD-95 | weight loss; restored blood adipokines to normal level; | HFD (Energy as 15% protein, 43% carbohydrate, and 42% fat); C57BL/6J mice; Male | [82] |
| Naringin | Grapefruit (Citrus × paradisi) | Daily oral naringin; 100 mg/kg + HFD; 20 weeks | ameliorated mitochondrial dysfunction, improved insulin signaling pathway, AMPK | weight loss; restored abnormal glucose, fatty acid, and cholesterol metabolism | HFD (unknown composition); C57BL/6J mice; Male | [83] |
| Panax japonicus saponins | Japanese ginseng (Panax japonicus) | Oral daily saponins; 15 mg/kg and 45 mg/kg; 16 weeks | decreased neurodegeneration and neuroinflammation; upregulated AMPA receptors signaling pathway | weight loss; antidepressant | HFD (60% total calories from fat); Balb/c mice; Male | [84] |
| Purple sweet potato color anthocyanins | Sweet potato (Ipomoea batatas) | Oral daily PSPC; 100 mg/kg + HFD; 20 weeks | enhanced autophagy, decreased levels of ROS; improved BDNF levels | weight loss; ameliorated peripheral insulin resistance | HFD (60% calories from fat); ICR mice; Male | [85] |
| Rhein | Rhubarb (Rheum rhabarbarum) | Daily oral rhein; 120 mg/kg + HFD; 6 weeks | improved BDNF levels; decreased neuroinflammation | weight loss; inhibited the increase in plasma LPS level and the proinflammatory macrophage accumulation in the colon and alteration of microbiota, improved glucose tolerance | HFD (60% fat by calories); C57BL/6J mice; Male | [86] |
| Roxburgh’s jewel orchid polysaccharides | Roxburgh’s Jewel Orchid [Anoectochilus roxburghii (Wall.) Lindl.] | Oral daily ARPs; (1 mg/g and 3 mg/g (w/w) + HFD; 14 weeks | decreased Tau phosphorylation; and neuroinflammation | weight loss; decreased plasma glucose, total cholesterol, inflammation; restored intestinal epithelial barrier; decreased abundance of Parabacteriodes | HFD (60% kcal from fat); C57BL/6J mice; Male | [87] |
| Sea-buckthorn flavonoids | Sea-buckthorn (Elaeagnaceae genus) | Oral daily Sea Buckthorn flavonoid; 0.06% and 0.31% w/w mixed in HFFD; 14 weeks | alleviated the synaptic damages, reduced neuroinflammation, normalized insulin signaling, increased neurotrophic growth factors levels | weight loss; reversed glucose intolerance increase and insulin sensitivity loss; significantly decreased TG, TC, LDL, significantly increased HDLs | HFHFD (45% kcal from fat, 10% fructose in drinking water); C57BL/6J mice; Male | [88] |
| Silymarin | Milk thistle (Silybum marianum) | Oral daily silymarin; 100 mg/kg and 200 mg/kg + HFD; 15 days | reversed increase in AChE activity; decreased oxidative stress; reduced nitrate/nitrite levels and myeloperoxidase activity; decreased brain neutrophil infiltration and Aβ burden | weight loss; lowered serum cholesterol level; | Cholesterol-rich diet; HFD (310 g/1000 g of total diet from fat); Swiss Albino mice; Male and Female | [89] |
| Tea saponins | Tea plant | Oral daily tea saponins; 0.5% mixed in HFD; 6 weeks | suppressed neuroinflammation; reduced microglia and astrocyte accumulation; raised BDNF levels | weight loss; reversed alteration of gut microbiota and systemic inflammation; reduced M1 macrophage accumulation in the colon; | HFD (60% energy from fat); C57BL/6J mice; Male | [90] |
| Xanthohumol Derivatives | Hops (Humulus lupulus) | Oral daily xanthohumol derivatives; 30 mg/kg; 13 weeks | not investigated | weight loss (TXN); improvement of impaired glucose tolerance; decreased HOMA-IR and plasma leptin | HFD (60% fat; 20% carbohydrate; 20% protein); C57BL/6J mice; Male | [91] |
Abbreviations: HFD: high-fat diet; HDL: high-density lipoprotein; AChE: acetylcholinesterase; BDNF: brain-derived neurotrophic factor; ROS: reactive oxygen species; AKT: serine/threonine kinase; PSD-95: postsynaptic density-95; AMPK: AMP-activated protein kinase.