A Systematic Review of the Protective Actions of Cat’s Whiskers (Misai Kucing) on the Central Nervous System

Abstract

Orthosiphon stamineus (OS) or Orthosiphon aristatus var. aristatus (OAA) is commonly known as cat's whiskers or "misai kucing". It is an herbaceous shrub that is popular in many different traditional and complementary medicinal systems. Its popularity has been justified by the plethora of studies that have shown that the secondary metabolites of the plant has effects that range from anti-inflammatory and gastroprotective to anorexic and antihypertensive. As such, OS could also be a potential treatment for Central Nervous System (CNS) disorders. However, a cohesive synthesis of the protective actions of OS was lacking. This systematic review was therefore commenced to elaborate on the various protective mechanisms of OS in the CNS. The PRISMA model was used and five databases (Google Scholar, SCOPUS, SpringerLink, ScienceDirect, and PubMed) were searched with relevant keywords to finally identify four articles that met the inclusion criteria. The articles described the protective effects of OS extracts on Alzheimer's disease, epilepsy, learning and memory, oxidative stress, and neurotoxicity. All the articles found were experimental or preclinical studies on animal models or in vitro systems. The reported activities demonstrated that OS could be a potential neuroprotective agent and might improve CNS conditions like neurodegeneration, neuroinflammation, and oxidative stress.

An integrative analysis to predict the Active Ingredients and explore Polypharmacological Mechanisms of Orthosiphon stamineus Benth. for human health

“…Different from Orthosiphol A, Rosmarinic acid, a water-soluble and absorbable polyphenol that been researched endlessly, had several exciting effects, including antioxidant(Shen et al, 2017), anti-inflammatory(Luo et al, 2020), anti-tumor(Kim et al, 2015), antimicrobial(Slobodnikova et al, 2013), anti-diabetic(Ngo et al, 2018), neuroprotective(Ghasemzadeh and Hosseinzadeh, 2020; Hasanein and Mahtaj, 2015) and nephroprotective activities(Domitrovic et al, 2014; Al-Dhabi et al, 2014) even cosmetic effects(Iwona and Katarzyna, 2020). Similarly, two flavonoids Eupatorin and Sinensetin also been confirmed to possess almost the same pharmacological effects as O. aristatus (Han et al, 2020; Laavola et al, 2012; Chung et al, 2020; Ashraf et al, 2018). Noteworthily, our results have shown that Rosmarinic acid cannot cross the blood-brain barrier and its gastrointestinal absorption was low (Table S2).…”

“…Noteworthily, our results have shown that Rosmarinic acid cannot cross the blood-brain barrier and its gastrointestinal absorption was low (Table S2). But the pre-clinical experiments showed that it can improve central system diseases such as epilepsy and Alzheimer’s disease(Ghasemzadeh and Hosseinzadeh, 2020; Hasanein and Mahtaj, 2015; Chung et al, 2020), which makes me confused. Anyway, we speculate that the O. aristatus own many ponderable ingredients for phytochemical screening and validation.…”

“…Besides, it seems compelling for O. aristatus to treat nephritis(Xu et al, 2020; Domitrovic et al, 2014; Luo et al, 2018), calculus(Akanae et al, 2010), urinary tract infection, hypertension(Azizan, 2012), liver damage(Yam et al, 2007), atherosclerosis(Mohd et al, 2019), and gastritis(Yuniarto, 2017) in numerous animal experiments. A few investigations also evaluated its neuroprotection in epilepsy, depression, and Alzheimer’s disease(Chung et al, 2020). However, most of these studies were at the pre-clinical phase; only three clinical trials of an herbal combination containing O. aristatus proved effective in treating hypertension, metabolic syndrome(Cicero et al, 2012), and urinary tract infections(Mainini et al, 2020; Vahlensieck et al, 2019).…”

“…Different from Orthosiphol A, Rosmarinic acid, a water-soluble and absorbable polyphenol that been researched endlessly, had several exciting effects, including antioxidant 35 , anti-inflammatory 36 , anti-tumor 37 , antimicrobial 38 , anti-diabetic 39 , neuroprotective 40,41 and nephroprotective activities 42,43 even cosmetic effects 44 . Similarly, two flavonoids Eupatorin and Sinensetin also been confirmed to possess almost the same pharmacological effects as O. aristatus 4,[45][46][47] . Noteworthily, our results have shown that Rosmarinic acid cannot cross the blood-brain barrier and its gastrointestinal absorption was low (Table S2).…”

Orthosiphon stamineus Proteins Alleviate Hydrogen Peroxide Stress in SH-SY5Y Cells

“…A plethora of studies on the crude extracts or secondary metabolites of OS has shown protective effects, including antioxidative, anti-inflammatory, antiproliferative, cytotoxic, and antiangiogenic effects [ 10 , 11 ]. Added to that, OS has recently been reported for its neuroprotective effects [ 12 ]. In another recent study, OS leaf proteins (OSLPs) alleviated pentylenetetrazol-induced seizures in adult zebrafish [ 13 ].…”