Salimuzzaman Siddiqui, (Urdu: سلیم الزّماں صدّیقی [səˈliːmʊzːəmaːn sɪˈd̪ːiːqi]; 19 October 1897 – 14 April 1994) was a Pakistani organic chemist specialising in natural products, and a professor of chemistry at the University of Karachi. Siddiqui studied philosophy at Aligarh Muslim University and later studied chemistry at Frankfurt University, where he received his PhD in 1927. Upon returning to British India, he worked at the Tibbia College Delhi and the Indian Council for Scientific and Industrial Research. He later migrated to Pakistan and worked in the Pakistan Council of Scientific and Industrial Research. He went on to establish the Pakistan National Science Council and was appointed its first chairman in 1961. In the same year he became a Fellow of the Royal Society. He later co-founded the Pakistan Academy of Sciences, and after retirement from his government job, he founded the Hussain Ebrahim Jamal Research Institute of Chemistry. Siddiqui is credited with pioneering the isolation of unique chemical compounds from the Neem (Azadirachta indica), Rauvolfia, and various other flora. As the founder director of H.E.J. Research Institute of Chemistry, he revolutionised research of the pharmacology of various domestic plants found in South Asia to extract novel chemical substances of medicinal importance. Siddiqui published more than 300 research papers and obtained 40 patents mainly in the field of natural product chemistry. In addition to his scientific talents, Siddiqui was also an avid painter, poet, and a connoisseur of Western music. His paintings were exhibited in the United States, Germany, India, and Pakistan.
Early life Salimuzzaman was born in Subeha (Barabanki District) near Lucknow on 19 October 1897. His father's name was Chaudhry Muhammad Zaman and his elder brother Chaudhry Khaliquzzaman was a distinguished All India Muslim League leader and one of the founding fathers of Pakistan. He received his early education from Lucknow, both in the Urdu and Persian languages, and soon developed interest in literature, poetry, and calligraphy from his father Sheikh Muhammad Zaman. He graduated in Philosophy and Persian language, from Muhammadan Anglo-Oriental College (that would later become Aligarh Muslim University) in 1920. In 1920, Siddiqui proceeded to University College London to study medicine. However, after one year of pre-medical studies, he moved to Frankfurt University in 1921 to study chemistry. In 1924, he married his German classmate, Ethel Wilhelmina Schneeman. He received Doctor of Philosophy under the supervision of Julius Von Braun in 1927. During his college days in Germany in the 1920s, Germany experienced high inflation and he went through some hard economic times. In these tough times, India's then eminent philanthropist Hakim Ajmal Khan used to send him Rupees400 every month. Many years later, as a successful scientist in Pakistan, Siddiqui repaid Hakeem Ajmal Khan's kindness by dedicating his discoveries to him. On his return, he established the Ayurvedic and Unani Tibbi Research Institute at the Tibbia College Delhi, under the guidance of Hakim Ajmal Khan. He was appointed its first director. However, soon after the death of Hakim Ajmal Khan, Siddiqui left the post. In 1940, he joined Indian Council for Scientific and Industrial Research where he worked until 1951 when he migrated to Pakistan on the request of Prime Minister Liaquat Ali Khan.
Pioneering research Siddiqui's first breakthrough in research came when he successfully isolated an antiarrhythmic agent in 1931 from the roots of Rauvolfia serpentina. He named the newly discovered chemical compound as Ajmaline, after his mentor Hakim Ajmal Khan who was one of the illustrious practitioners of Unani system of medicine in South Asia. Later on, Siddiqui also extracted other alkaloids from Rauvolfia serpentina that included Ajmalinine, Ajmalicine (C21H24N2O3), Isoajmaline, Neoajmaline, Serpentine and Serpentinine. Many of these are still used worldwide for treatment of mental disorders and cardiovascular ailments, especially as antiarrhythmic agents in Brugada syndrome.
Discoveries from Neem
Siddiqui was the first scientist to bring the anthelmintic, antifungal, antibacterial, and antiviral constituents of the Neem tree to the attention of natural products chemists. In 1942, he extracted three bitter compounds from neem oil, which he named as nimbin, nimbinin, and nimbidin respectively. The process involved extracting the water-insoluble components with ether, petrol ether, ethyl acetate and dilute alcohol. The provisional naming was nimbin (sulphur-free crystalline product with melting point at 205 °C, empirical composition C7H10O2), nimbinin (with similar principle, melting at 192 °C), and nimbidin (cream-coloured containing amorphous sulphur, melting at 90–100 °C). Siddiqui identified nimbidin as the main active antibacterial ingredient, and the highest yielding bitter component in the neem oil. These compounds are stable and found in substantial quantities in the Neem. They also serve as natural insecticides. In acknowledgement of these revolutionary discoveries, he was awarded the Order of the British Empire in 1946. In his later career, Siddiqui continued to discover and isolate numerous unique anti-bacterial compounds from various parts (leaves, bark, etc.) of the Neem and other plants. He had more than 50 chemical compounds patented in his name in addition to those discovered as a result of his joint research with other colleagues and students. Most of these discoveries still remain vital natural ingredients of various medicines as well as biopesticides.
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