Is Cukur Manis or Mani Cai Safe for Consumption?

 Nutritional Anaemia and Hypotension Among Rural Malaysian Women: Investigating the Role of Sauropus androgynus (Cekur Manis)

by  Lim Ju Boo alias Lin Ru Wu

Abstract: 

This paper explores the relationship between dietary patterns in rural Malaysian villages and the prevalence of nutritional anaemia and hypotension among young women, with a specific focus on the widely consumed vegetable Sauropus androgynus (cekur manis). Through field studies and chemical analyses, a potential link was established between frequent consumption of this vegetable and observed low blood pressure. The phytochemical component papaverine, a vasodilator, was identified in the plant. This paper discusses the dual nature of S. androgynus as both a nutritional and potentially toxic plant, citing documented outbreaks of bronchiolitis obliterans in Taiwan and Japan from the raw consumption of the plant in large quantities. Recommendations for safe consumption and further public health implications are provided.

1. Introduction:  During medical research and health surveys conducted by my medical and nutrition team from the Institute for Medical Research from 1970 till mid 1990's in the villages of Malaysia, a recurring health problem among young women was observed, namely, frequent complaints of giddy spells, later correlated with nutritional anaemia and consistently low blood pressure. These women, often on nearly meatless diets, experienced chronic iron deficiency worsened by monthly menstrual blood loss.

Upon deeper investigation, it was discovered that many of these villagers consumed large quantities of a local leafy vegetable known as cekur manis (Sauropus androgynus), valued for its affordability, taste, and traditional health benefits, and easy to plant in their own village fields and compounds. 

Intrigued by the potential physiological effects of this plant, samples of cukur manis were collected by one of my colleagues from the National University of Malaysia (UKM), and sent  to the Dept. of Nutrition at Queen Elizabeth College (QEC), University of London where we once studied -  for chemical analysis. There at QEC they used their mass spectrometers and nuclear magnetic resonance (NMR) spectrometers to identify the  compound present. It turned out to be papaverine, a smooth muscle relaxant that has hypotensive properties. Of course we can also use other analytical procedures such as spectroscopy (UV-Vis, FTIR) and chromatography (GC-MS, HPLC-MS), but magnetic resonance (NMR) spectrometers is better, and we did not have that analytical instrument.  

An NMR spectrometer is huge and a complex instrument, not easily visualized without prior knowledge, nor is it easy to use,  but it's essentially a huge machine  that uses strong magnetic fields and radio waves to analyze the magnetic properties of atomic nuclei within a sample. 

NMR (Nuclear Magnetic Resonance) spectroscopy is a powerful tool for elucidating and identifying the molecular structure of a compound. It provides detailed information about the connectivity of atoms within a molecule, as well as their chemical environment, which helps in determining the overall structure.

While not  simple to use, modern benchtop NMR spectrometers have become more user-friendly, with integrated consoles and software to aid in data acquisition and interpretation.

We did not have an NMR spectrometer in Malaysia then in the 1970's, so we sent samples of cukur manis to scientists at the Department of Nutrition and in the Department of Chemistry at Queen Elizabeth College, University of London to help us identify the unknown compound that causes hypotension. The scientists at QEC identified it as papaverine.

2. Nutritional Composition and Traditional Use S. androgynus is commonly consumed in Southeast Asia, known locally as cekur manis (Malay), mani cai (Chinese), or sweet leaf. Rich in iron, protein, vitamins A, B, and C, calcium, potassium, and carotenoids, it has been used traditionally to:

• Promote lactation

• Support skin and eye health

• Improve vitality and digestion

3. Field Observations and Clinical Correlation In the studied villages, the majority of women consumed cekur manis in cooked form, often stir-fried. No cases of respiratory distress or lung disease were reported, but hypotension was consistently noted. This prompted the hypothesis that a phytochemical component in cekur manis might be acting as a vasodilator.

4. Phytochemical Analysis: As already mentioned, laboratory analysis confirmed the presence of papaverine, an opium-derived but non-narcotic alkaloid known for its ability to relax smooth muscle tissues, particularly those of blood vessels. Papaverine’s pharmacological actions include:

• Dilation of cerebral and coronary arteries

• Smooth muscle relaxation in the gastrointestinal and genitourinary tracts

• Temporary blood pressure lowering effects

Although once used in the management of vascular diseases, papaverine is no longer widely prescribed for hypertension due to its:

• Short duration of action

• Potential hepatotoxicity

• GI and CNS side effects

• Unpredictable pharmacokinetics

The naturally occurring papaverine in cekur manis likely explains the consistent hypotension observed in the villagers, compounded by anaemia from poor iron intake.

5. Toxicity Concerns and International Incidents Between the 1990s and early 2000s, Taiwan and Japan saw multiple cases of bronchiolitis obliterans, a rare and irreversible lung disease, linked to the excessive raw consumption of S. androgynus. Young women consumed large quantities of raw cekur manis in juices or smoothies, often for weight loss or to enhance lactation.

Over 100 cases in Taiwan required long-term oxygen therapy, some requiring lung transplants [Chen et al., 2000].

The suspected mechanism involves certain alkaloids and non-protein amino acids that induce immune-mediated inflammation and fibrotic scarring of bronchioles.

The specific compound in raw Sauropus androgynus (cukur manis) that causes bronchiolitis obliterans has not been definitely identified. However, it is believed that certain compounds within the plant, particularly in the aqueous fraction, may be responsible for inducing lung inflammation and tissue damage. Studies suggest that the aqueous fraction of S. androgynus may play a significant role in the development of the disease. 

Several compounds have been isolated from S. androgynus, including nucleosides,  flavonols, and lignan glycosides, none have been definitively pinpointed as the sole cause of bronchiolitis obliterans.

T-cell Mediated Immunity:

Research indicates that T-cell mediated immunity might be involved in the pathogenesis of lung damage, suggesting an immune response is triggered by the plant's compounds.

Crucially, no cases were associated with cooked cekur manis, suggesting the  toxic compounds is destroyed during cooking (heat-labile).  

6. Recommendations and Public Health Implications Given the dual nature of S. androgynus ,  as a nutrient-dense vegetable and a potential source of toxicity, public education is essential:

Encourage consumption in moderation and only in cooked form, bear in mind cekur manis is  known to be rich in beta-carotene, which is a precursor to vitamin A (retinol). This means that the body can convert the beta-carotene found in cekur manis into vitamin A. Studies have shown that cekur manis contains a high level of total carotenoids, which are converted to retinol equivalents (RE). 

Avoid large quantities of raw cekur manis, especially in juice or smoothie form. Continue research to identify the exact causative toxic compounds

7. Conclusion:

The study highlights how local diets, when examined in conjunction with phytochemical analysis, can reveal both therapeutic and harmful health effects. The vasodilatory property of papaverine in cooked S. androgynus may explain low blood pressure among rural Malaysian women, especially those also affected by anaemia. However, international cases of bronchiolitis obliterans from raw consumption underscore the need for caution. Traditional wisdom and modern science must work hand-in-hand to ensure safe dietary practices.

References:

1, Chen CH, Shih CL, et al. (2000). Sauropus androgynus-induced bronchiolitis obliterans in Taiwan: a review of epidemiology, clinical presentations, and pathogenesis. Am J Respir Crit Care Med, 161(4): 1241–1246. PMID: 10764302

2. Ismail A, et al. (2000). Nutrient composition of selected indigenous vegetables in Malaysia. Food Chemistry, 68: 51–59.

3. Wong KC, Tan GL. (1995). Chemical constituents and biological activities of Sauropus androgynus. Natural Product Communications, 2(6): 199–204.

4. Wu CC, et al. (1997). Obliterative bronchiolitis associated with consumption of Sauropus androgynus in Taiwan. Lancet, 349: 1306.

5. Liu GY, et al. (2006). Papaverine and its pharmacological applications: past, present and future. International Journal of Clinical Pharmacology and Therapeutics, 44(9): 480–488.